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NAROO Mask F.U+ Review – The Most Breathable Mask?

NAROO Mask is a Korean-based sports mask company that has one of the largest collections of masks that I’ve seen. Whether you are looking for protection from pollen, UV, cold temperatures, or inhalable particles (such as PM2.5) NAROO Mask has masks to help.

While NAROO Mask focuses primarily on sports masks, they also make a range of daily masks. Today, I want to give particular attention to their F Series of masks (F = filtration). These are the masks designed for filtration against fine particles such as those commonly found in air pollution

Over the past couple of weeks, I have been testing four models of NAROO Mask – two more standard mask designs (the F.U+ and F.U+ Copper), along with two bandana-style masks (the F5s and F1s). Since the F.U models differ greatly from the F1s and F5s I decided to split this NAROO Mask review into two parts.

This first article will cover the more standard mask designs used in the F.U variants. If you are interested in the neck-based design of the bandana-style masks, make sure to check out my review of the F1s and F5s from NAROO Mask. Where the F.U+ variants are a good choice for daily use, the F1s and F5s are much more exercise and activity-focused.

Before jumping straight into this review I want to clarify two points. 

  1. Every mask will fit each wearer differently. In my reviews I do my best to share my honest thoughts on the fit and mask leakage. However, I can not say whether or not this mask will fit you – unfortunately, the only way to know this for sure is to try the mask yourself.
  2. The filtration results in this article apply to the filter media. To achieve the best protection, a correct fit and seal without leaks is required. 

With that being said, I am excited to share my review of NAROO Masks. As someone living in Korea, I am always excited to see what masks are being designed and created locally. Further, I’ve had many requests to review these masks from readers in the past few months. For both of these reasons, I look forward to trying and sharing my thoughts on both the F.U+ and F.U+ Copper!

Save 10% on NAROO Masks with the code ‘Ethan2021’

This post contains affiliate links. For more information, please refer to my affiliate disclaimer. I was sent a product for review, but the article is not sponsored. All opinions expressed in this post are my honest thoughts. I only recommend products that I genuinely believe in.

Information on this blog is for informational purposes only. Readers are encouraged to confirm the information herein with other sources. Furthermore, this information is not intended to replace medical advice from professionals. This website assumes no responsibility for the accuracy of the information, and information is subject to change without notice. Devices mentioned on this website are not medical devices and do not guarantee protection.


Naroo Mask Micronet Filter

The filter used in all F Series NAROO Masks is called the MICRONET™ filter and it is an exclusive filter design that only NAROO uses. Unlike most traditional filters, it is not a melt-blown filter meaning that it has a range of benefits as well as some disadvantages.

Before going any further, I want to note that the tests carried out on NAROO Masks apply to the filter rather than to the mask itself. For the best protection, the mask must be fitted correctly as per the manufacturer’s instructions and with no leaks. 

I visited NAROO’s office to verify the test certificates referred to in this section. They are not currently publicly available. I believe that all such certifications should be public and I hope that this is a change made in the future. With that being said, NAROO does have the certificates reflecting the information stated below and I have personally seen these and referred to them for this article.

The MICRONET™ filter has been tested by an independent third-party laboratory in Japan. This laboratory tested the filter against particles in the 1.7μm to 2.6μm size range. NAROOachieved > 99.9% filtration across the tested samples.

This testing was carried out at a larger particle size than standard mask/filter testing which is often carried out at 0.3μm (MPPS) or even 0.1μm. The testing size range (1.7μm to 2.6μm) shows that the mask will be capable of filtering both PM10 and most PM2.5 particles. However, the masks do currently lack filtration testing for smaller particles.

MICRONET™ filters are very stretchable and the mask feels very elastic-like. This means that the filter media can be stretched at times, and you may be able to see very small holes in the fabric. NAROO has thought about this and testing has also been carried out on their filters while stretched. The stretched filters also showed > 99.9% filtration.

Naroo Mask Filter

Since the filter relies on microfibres for filtration it retains high filtration efficacy even after being washed. Meltblown filters tend to rely heavily on electrostatic filtration – a filtration that is very effective, but quickly wears off as the filter loses charge. Washing expedites this process and after contacting water, many melt-blown filters are virtually useless. 

Nanofibre and microfibre filters, on the other hand, rely more heavily on mechanical filtration mechanisms. These mechanisms are far more durable and not only filter for longer, but they can retain a high level of filtration even after being washed.

NAROO has had an independent third party laboratory carry out wash-cycle testing on the filter media and it shows very little decrease in the filtration efficacy even after 100 washes. After 100 washes, the filters still maintained a filtration rate of > 99.8% against 1.7μm – 2.6μm particles. 

Testing beyond 100 cycles was not possible due to lab restrictions. While it’s likely that the masks will retain filtration even beyond 100 washes, NAROO recommends replacing the mask around the 100 wash mark. The lifespan of the mask will be covered in further detail in the lifespan section of this article.

NAROO Mask’s F.U+ Copper also features copper treated fibres within the MICRONET™ filter. Copper filters have become popular due to the pandemic and many masks have been adding such filters. Copper is added in order to inactivate certain particles, including viral particles.

Through third-party lab testing, the filter on the F.U+ Copper was shown to have > 99% bacterial particle filtration. However, at the time of writing this article, there has been no testing on viral particles.

Considering that the addition of copper adds $10 to the total price of the mask it’s up to you whether or not this extra will be worth it. Copper can be effective against viruses but viral load lab testing, there is no way to tell how effective it is in its implementation on both NAROO Mask and other reusable masks.

Save 10% on NAROO Masks with the code ‘Ethan2021’


Naroo Mask with Copper scaled

Fit is equally as significant, if not more so, than filtration. While the theoretical filtration capabilities of a mask are very important, none of this will matter if the mask doesn’t seal properly. Air will take the path of least resistance and a mask with leaks will not be filtering the air that you breathe. 

The F.U+ and F.U+ Copper are masks that follow a traditional mask design in regards to fit. That is to say, they both follow a design that looks quite similar to a tight-fitting surgical mask. They both have adjustable earloops, wire nosepieces, and seal just under the chin. 

Both the NAROO Mask F.U+ and F.U+ copper are offered in three sizes – XS, S and L. These masks follow the dimensions below:

  • Extra small – 9.5cm (width) x 13cm (length)
  • Small – 16cm x 10.5cm 
  • Large – 18cm x 12cm 
Naroo Mask Fitting Dimensions

These lengths are measured from cheekbone to cheekbone (width) and nose bridge to (slightly behind) the chin (length). Most people will be able to find a fit among these three sizes. Personally, I opted for the S variant as I have a small face. Initially, the mask felt slightly too small, but after adjusting the earloops it fit comfortably.

I would recommend the large size for anyone who usually wears a medium or large from other mask brands. If you usually go for a small, then the small from NAROO should also fit. The extra small seems to be aimed at children as there is a very big size difference between XS and S.

Within each size, there is little room for adjustment via the earloops. The loops are adjustable and you can easily tighten or loosen them about 3-4cm each way. This will allow the mask to fit most facial dimensions provided you have the right size mask.

The MICRONET™ filter that the mask uses is elastic-like and this allows some flexibility when it comes to fitting. Since the fabric has filtration testing even when stretched, it’s safe for it to be stretched somewhat. With that being said, it’s important to pick the right size initially for the best comfort.

When it comes to masks and respirators, there are usually two areas where leaks often occur. One of these is around the bridge of the nose, and the other is along the bottom of the mask seal – usually around the jawline or on the chin. More often than not, masks lack proper sealing when it comes to one, or both, of these areas.

During my time testing both masks, I found that the seal along my jaw (slightly behind it) was solid. It rarely ever leaked and if it did, it was not noticeable. This was largely caused by the quite tight fit of the mask, and because it sits very flush with my face compared to other masks.

On the other hand, I had some issues with the seal on my nose. It was very hard to adjust the wire to a mould that fit my nose well and this was my biggest issue during my time trying the F.U+ masks from NAROO. 

Naroo Mask F.U in Blue

The wire is stiff and quite short. Usually, stiff wires are better than more malleable designs as they hold their shape better (leading to a longer-lasting seal). However, I had difficulty adjusting the wire so that it fits around my nose without leaving gaps. I’m not sure if this is because my nose has quite sharp angles, or if it is due to the wire being a bit too stiff. Either way, I wasn’t able to fully remove leaks around my nose.

The nose wire is also quite short and ends right where my nose meets my face. I believe that expanding the wire and making it more easily adjustable would improve the fit significantly. Another potential idea that I have not yet tested is adding a strip of memory foam to the inside of the mask. I believe this would improve the nose leakage significantly.

Overall, from my experience, the NAROO Mask F.U+ has a decent fit but there are improvements that could be made along the top of the mask. Nearly every cloth mask that I have tried has leaks around my nose, and this is not an issue unique to NAROO. I would be interested to hear more experiences with the fit of these masks. If you have tried them, please feel free to share your thoughts below!

Save 10% on NAROO Masks with the code ‘Ethan2021’


Naroo Mask F.U Biege

When it comes to comfort on masks there are two main factors that I like to consider – breathability and microclimate. Often, these two factors are strongly related as lower breathability (and hence, airflow) usually leads to more humid and hot conditions inside the mask.


The NAROO F.U+ and F.U+ Copper sit flush across my face. This is something that surprised me, as it’s been a while since I’ve regularly worn a mask without a chamber-like area in front of my mouth. It’s quite common for masks to have such an area to allow the wearer to breathe more easily.

While this can help to prevent the filter from interfering with breathing, it can also create a microclimate within the mask that is very humid and hot. This can often lead to discomfort, especially in hotter months.

I mention this because many people reading this may be more familiar with these masks. Even standard N95, KF94, and KN95 respirators normally have a large chamber between the wearer’s face and the mask. NAROO Mask is very different, however, and it sits on the wearer’s face rather than in front of it.

When it comes to comfort, this design has both advantages and disadvantages. It helps to keep the breathing resistance considerably lower and reduces ‘dead zones’ within the mask. On the other hand, since the F.U+ masks sit so close to my face they can interfere with breathing – I found this to be especially common when exerting myself and needing to breathe through my mouth.

The F.U+ models of NAROO Mask are intended to balance breathability and filtering but I do believe that other NAROO masks are better suited for exercise. However, there will always be times when we are under some level of exertion and need to breathe more heavily.


Breathability on both of the NAROO Mask models is excellent. The MICRONET™ filter that all of the masks in the F Line use allows for a lot of airflow by providing very little breathing resistance. While I currently don’t have access to a method to objectively test this, I feel like the breathability in the NAROO Mask F.U+ is one of the highest amongst reusable masks with a non-replaceable filter.

I usually refer to nanofibre masks such as Happy Masks and Bloo Mask as the ‘gold standard’ for breathability. Both of these masks provide minimal breathing resistance and allow for airflow that almost feels unhindered. NAROO Mask breathability feels close to these masks and I am impressed with how breathable the F.U+ is.


Naroo Mask F.U Copper

The F.U+ and F.U+ Copper follow the conventional mask approach when it comes to fitting. Both models use earloops rather than relying on a headband or neckband (in the case of masks such as Purar or CosyPro). Earloops have a few key strengths and weaknesses.

Earloops are undeniably the easiest design to don and doff. If you are in a situation where you find yourself needing to remove (or pull down) and then put it back on regularly, earloops are far more convenient. Not only are they easier, but unlike head-band based designs they won’t ruin your hair when moved.

However, head-band based designs also generally have a firmer fit and are more comfortable over longer periods of wear. Our ears are quite sensitive after wearing a mask for a few hours, and it’s common to experience some pain where the straps loop around. Head-bands remove this issue by placing the pressure on the back of the head instead.

The NAROO F.U+ and NAROO F.U+ Copper both use earloops and experience both the strengths and weaknesses of such a design. From my experience, the earloops are comfortable for a couple of hours, but they can cause some pain after being worn for more than a few hours. This isn’t an issue restricted to NAROO Masks. Rather, it is something that I experience with nearly all ear strap designs.

It is also worth mentioning that headband accessories are very cheap and can easily be picked up on Amazon and many other shopping sites. These accessories are normally little pieces of plastic that simply pull the earloops together behind your head.

Filter Interference

Since the F.U+ models sit so close to the wearer’s face, there is filter interference. When I say filter interference, I am referring to the filter being sucked in when you breathe. While the filter should always be getting sucked in on a sealed mask when the wearer inhales, it can cause problems if it actually gets sucked into the wearer’s mouth.

When breathing through my nose (which was most common in my typical daily life) I experienced no issues with interference. When breathing through my mouth, I never experienced the filter going into my mouth, but it would be pulled against my lips every time I inhaled. 

Since the inner layer of the mask appears to be some kind of microfibre, I didn’t find this overly bothersome. But, it is worth keeping in mind that the inner materials of the mask will interfere with heavy breathing.

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Cost & Lifespan

Both the NAROO F.U+ and F.U+ Copper are competitively priced masks compared to other non-replaceable filter options on the market. Coming in at $20 and $30 respectively, the F.U+ Copper is very similarly priced to the most popular masks in this segment – Cambridge Mask and Vogmask. The F.U+ comes in significantly cheaper.

NAROO F.U+ Copper$30
Cambridge Mask$32
Happy Masks$24

Cambridge Mask Pro, Vogmask VMC & Happy Masks Pro prices used

There is no definitive lifespan for either of these mask variants. As discussed in the filtration section, these masks are capable of retaining high filtration efficacy even after 100 wash cycles. If you are washing your mask every few days and looking after it, you can theoretically use the mask for a year.

However, there are other factors to consider. Every time you wash the mask, breathability will decrease slightly. This usually isn’t a factor in the short term, but it may be noticeable after a few months of using the mask and regularly washing it. On top of this, masks can begin to smell and have loose fibres over the course of their life.

Naroo Mask Washing Instructions

NAROO Mask washing instructions.

There is no specific lifespan for NAROO Masks and when I asked NAROO they said that they would recommend replacing the masks around the 100 washes mark. While the masks should, in theory, maintain filtration even after 100 washes, they have not been tested for more due to lab limitations. 

If you are washing your mask every day, then expect around 3 months of usage. If you are washing it every few days, it can easily last longer. Personally, I never wear masks for more than 6 months mainly due to hygiene. 

Overall, the F.U+ and F.U+ Copper are far more affordable than disposable alternatives. Further, they are cheaper than many alternatives that use a non-replaceable filter. Interestingly, even when factoring in replaceable filter masks, these two particular NAROO Mask models are very often cheaper.

Save 10% on NAROO Masks with the code ‘Ethan2021’


Naroo Mask F.U

Both the NAROO Mask F.U+ and F.U+ Copper are masks worth considering if you are looking for a new form of pollution protection. The masks are affordable, long-lasting and tests have shown that they are capable of both high initial filtration efficiency and retaining high efficiency after many wash cycles.

Although the MICRONET™ filter has not been tested against particles finer than 1.7μm, the filter has been shown to be very effective against PM2.5 and PM10 particles. However, since no testing on smaller particles has been carried out, the filtration of ultrafine PM1 (1.0μm particles) and smaller is unknown.

The breathability of both masks is very good, and this leads the masks to be comfortable to wear. The only issue I have when it comes to comfort is regarding filter inhalation – it’s quite easy to suck in the filter and pull it against your lips. Otherwise, these masks are both some of the more comfortable masks that I have tested.

When it comes to fit, I had trouble adjusting the wire nosepiece to fit my nose. However, I believe this would be less of a problem for people with flatter or/and wider noses. The mask sealed almost perfectly around my chin and jawline and this is a common leakage point among other reusable cloth masks.

Even the more expensive F.U+ Copper mask will be far cheaper than disposable masks and even many reusable masks with replaceable filters in the long run. If you are looking for a new mask, the masks from NAROO Mask are definitely worth considering.

If you are looking for more active masks, I have also written an article on the F1s and F5s from NAROO. These masks feature many of the same strengths as the F.U+ and F.U+ Copper, but they are designed for more active use.

If you’ve used any of the masks discussed in this article I would love to hear your thoughts. What were the strengths and weaknesses of the masks? All of this information helps not only me but also future readers.

Save 10% on NAROO Masks with the code ‘Ethan2021’


Has the F.U+ Mask Been Lab Tested?

Yes. Both mask variants have had filtration carried out by an independent third-party laboratory.

Does the F.U+ Mask Have an Official Certification?

NAROO Mask has official test results, but no official filtering grade (such as N95, KN95, KF94, etc).

Should I Buy the F.U+ or F.U+ Copper?

The F.U+ and F.U+ Copper masks are identical in every way with the exception of an added copper layer in the F.U+ Copper. Copper can kill germs on the surface over a period of time (usually a few hours).

What Are Some Alternatives to NAROO Mask?

If you are looking for reusable masks without replaceable filters Cambridge Mask and Vogmask are two popular choices. Here is a list of even more alternatives.

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