FAQ |  Frequently Asked Questions

General information about protective masks  

A surgical mask is a disposable medical device which complies with EN 14683 standard. It prevents the wearer from spreading droplets and protects him from droplets produced by other persons at close distance. It may not protect from inhaling the very small particles suspended in the air that potentially carry viruses, which means it will not prevent the wearer from potential virus contamination. 

There are 3 types of surgical mask:

  • Type I: bacteria filtering effectiveness > 95%.

  • Type II: bacteria filtering effectiveness > 98%.

  • Type IIR: bacteria filtering effectiveness > 98% including a splash resistant layer to protect against blood and other bodily fluids. 

A respirator or FFP mask (“Filtering Face piece Particles”) is a respiratory protective device which complies with standard EN 149 (equivalent to other international standards known as N95 in USA and KN95 in China).  

  •  It is tight fitting and creates a facial seal 

  •  It protects the wearer against the inhalation of both droplets and particles suspended in the air 

  •  It offers a higher level of protection, which limits wear comfort and may cause discomfort during prolonged use 

 Some of these respirators are equipped with an exhalation valve (mostly FFP3) to allow ease of breathing. However, such valves cause FFP respirators to not prevent spreading of pathogens by the wearer and are therefore not recommended in a pandemic context. Respirators are available in many different shapes, forms and sizes. They fall under 3 different categories, according to their filtration efficiency. 

  •  FFP1 filter at least 80% of aerosols, inward leakage < 22% 

  •  FFP2 filter at least 94% of aerosols, inward leakage < 8% 

  •  FFP3 filter at least 99% of aerosols, inward leakage < 2%, typically used for handling asbestos 

 The abbreviation NR or R is generally added after the FFP class. 

 NR    (not reusable), if the use is limited to one working day 
 R    (reusable), if it can be used for more than one working da

Surgical masks and respirators have different functions and objectives. 

 Surgical masks are loose fitting and designed for one-way protection to protect others from coughs and sneezes. They are not designed to protect the wearer. Certified surgical masks type II/IIR must be able to filter 98% of particles with a diameter of 3.0μm. 

 FFP2 respirators are tight-fitting masks designed for two-way protection. It creates a facial seal and filters both inflow and outflow of air. The fit is a very important characteristic to avoid air leakage from the sides of the mask. FFP2 are able to filter 94% of particles with a diameter of 0.45μm and a maximum of 8% leakage to the inside. 

Bacteria are relatively larger as compared to viruses, ranging generally between 0.2 and 2.0 μm in diameter.  Some of the smallest viruses may range from 20 to 30 nanometer (nm) in diameter with the majority of viruses ranging between 10 and 300 nm in diameter (0.01 and 0.3 μm). Covid19 has a diameter of approx. 60-140 nm (0.06-0.14 μm). 

Surgical masks  are recommended for:

  • health workers in low-risk medical settings.

Respirators,  FFP2 or FFP3 , are recommended for:

  • health workers and caregivers who are:

    • in close contact with confirmed or suspected virus-infected patients

    • in areas where aerosol generating procedures are undertaken

  • Risk groups:

    • People aged 60+

    • People of any age underlying health conditions, incl. chronic respiratory disease, cardiovascular disease, cancer, obesity, immunocompromised patients and diabetes mellitus.

Non-medical & fabric masks  are recommended for the general public and people who are not underlying health c onditions.

FFP respirators provide a higher level of protection than so called community, hygiene or surgical masks. However, because of the tight fit and the superior filter efficiency, they have more breathing resistance sometimes causing a feeling of suffocation or headaches. They are generally heavier than surgical masks. Consequently, people may tend to remove their masks more often, exposing them and others to a higher infection risk. 

People with a respiratory condition (e.g. asthma), high blood pressure, claustrophobia, pregnant woman should follow the advice or consult their doctor or other medical health professionals before using an FFP mask. Respirators with a valve are not recommended: although it makes breathing easier, it does not prevent others from being infecte

Before FFP respirators can be placed on the market in Europe, testing bodies carry out so-called conformity assessment procedures to certify the protective performance. The European PPE Regulation (2016/425) regulates the exact labelling requirements for respirators.

It is important to verify:

  • CE mark

  • adjacent to the CE mark, the test body (4-digit number)

  • CE certificate through approved EU notified body.

  • ink used for labelling is safe and does not cause skin irritation.

  • fit of the FFP mask


General description

It’s the world’s first CE-certified nanofiber surgical respirator with virus-trapping and bacteria-killing properties. Using Swiss award-winning nanofiber technology, it has been designed to provide maximum respiratory protection for the wearer against dangerous airborne contaminants including the most penetrating particle size (MPPS). 

While particulate matter or organisms of any size can cause adverse effects to our health, MPPS are especially dangerous. These are small enough to be absorbed directly into our bloodstream and enter our lungs, heart, and brains. NASK cutting-edge nanofiber technology is outstanding at both capturing the hardest particles size under 0.3 μm and protecting health care workers and risk groups from transfer of microorganisms, body fluids and pathogens

The initials NASK stands for  N anotechnology,  A nti-dust,  S afe and  K illing Bacteria. 

It is all at once!

FFP2 NR respirator and medical surgical mask able to kill over 99% bacteria on contact and to filter over 99% of dangerous airborne contaminants, ranking it equally with FFP3 respirators, which provides the highest level of protection. NASK NANOFIBER RESPIRATOR has been developed to use latest advances in nanofiber technology to create a highly protective and breathable bactericidal surgical respirator. The adjustable cushioning nose foam guarantees maximum sealing while ensuring comfortable fit and avoiding eyewear fogging. Ultra-thin, feather light (3.6g) and moisture resistant, it delivers a unique wearing comfort for 8+ hours of continuous use.

Before use, users must read and understand general instructions included in the packaging to ensure proper donning and seal.  

Nanofiber technology

NASK nanofibers are produced by using a patented technology with the ability to hold electrostatic charges. The outstanding NASK nanofiber properties include a feather light and extremely thin diameter as thin as 3/1000 a human hair combined with a high specific surface area

NASK advanced electrospun nanofibers are spinned and weaved into multiple layers composed to manufacture NASK NANOFIBER RESPIRATOR. They provide a much higher surface loading capacity than conventional respirators, resulting in superior filtration efficiency, breathability and comfort for 8+ hours of continuous use. 

Using advanced electrospun nanofibers, NASK NANOFIBER RESPIRATOR has a much higher surface loading capacity than conventional respirators. The patented technology used results in superior filtration efficiency of ≥99% against dangerous airborne contaminants, thereby conferring it the filter efficiency of an FFP3 which provides the highest level of protection.

  • ≥ 99% Filtration Efficiency by sodium chloride particles (class FFP3)

  • ≥ 99% Bacterial Filtration Efficiency 

  • ≥ 99% Viral Filtration Efficiency 

  • ≥ 95% Filtration Efficiency by oily particles 

Yes, NASK NANOFIBER RESPIRATOR is proven to kill  99% of bacteria in less than 5 minutes as tested by Nelson Lab (USA). 

The microscopic spear-shaped nanofibers capture bacteria by electrostatic attraction, break-down their cell surface, thus killing bacteria in less than 5 minutes as tested by Nelson Labs USA. 

NASK NANOFIBER RESPIRATOR can not only filter particle size smaller or greater than 0.26 -0.3 microns - but also the so called Most Penetrating Particle Size (MPPS|PM2.5), known  to be the hardest particle size to capture*. Small particles can include fungal spores (2 to 5 μm), bacteria (0.3 to 10 μm), or viruses (0.02 to 0.3 μm). Biological organisms may be carried on other particles including dust, blood and saliva. They are especially dangerous for human health. These are small enough to be absorbed directly into our bloodstream and enter our lungs, heart and brains. 

This allows virus such as SARS-CoV-2, H1N1, Ebola and influenza to be filtered out.  

*Brownian Motion: random motion of particles suspended in a fluid (a liquid or a gaz) resulting from their collision with the fast-moving molecules in the f luid.

Intended use
  • Mainly for healthcare workers and caregivers who are:

    • in close contact with confirmed or suspected virus-infected patients

    • in areas where aerosol generating procedures are undertaken

  • Risk groups: 

    • People aged 60+

    • People of  any age underlying health conditions, incl. chronic respiratory disease, cardiovascular disease, cancer, obesity, immunocompromised patients and diabetes mellitus.

  • All others who do not want to compromise on protection.

Yes, NASK NANOFIBER RESPIRATOR assures a two-way protection by filtering effectively both inflow and outflow air.

The United Nations Children's Fund and the World Health Organization recommend that face masks are used for children aged six years and older. The guidance recommends a risk‐based approach for children aged 6–11 years of age and children aged 12 and over should be treated as adults when it comes to wearing masks. FFP2 masks are recommended particularly for high‐risk children. 

Conventional FFP2 or FFP3 masks make breathing difficult and therefore, are not recommended to be used by pregnant women. Thanks to its advanced nanofiber technology, NASK NANOFIBER RESPIRATOR ensures a higher level of breathability and may be recommended for pregnant women in high risk areas during limited use. However, pregnant women and high-risk children are advised to follow the advice or consult their doctor or other medical health professionals before using an FFP respirator.

NASK NANOFIBER RESPIRATOR has been tested with sodium chloride and paraffin aerosols and developed to be used in healthcare settings. However, its superior features endow it with the ability to be used in various industrial setting such as but not limited to food processing, pharmaceutical manufacturing, cosmetic, construction and mining. 

NASK NANOFIBER RESPIRATOR is not built for vapor and gas filtration

Yes, NASK NANOFIBER RESPIRATOR is safe for human health. It has been tested by reputable international laboratories. Tests done include inhalation toxicity, oral toxicity, dermal irritation tests and toxicological risk assessment with proven results.


No b urden to manage different sizes. NASK NANOFIBER RESPIRATOR is available in one size that fits all. S-shaped clips i ncluded in the packaging  allow to adjust to different head sizes for individual comfort.

One box of NASK NANOFIBER RESPIRATOR contains 50 pieces and 100 two S-Shaped clips.


Yes, NASK NANOFIBER RESPIRATOR has been classified as Class I Medical Device Type IIR.

Yes, NASK NANOFIBER RESPIRATOR has been certified as CE category III FFP2 NR respirator, making it the worldwide first CE-certified bactericidal nanofiber respirator approved by a duly accredited European notified body (BSI UK – CE2797).

Compliance with norms EN 149:2001+A1:2009 and EN 14683:2014 classifies the NASK NANOFIBER RESPIRATOR as a CE category III FFP2 NR respirator and as a medical surgical mask Class I Type IIR. 

NASK NANOFIBER RESPIRATOR has been approved after comprehensive conformity tests run by esteemed laboratories such as Nelson Lab (USA), BSI (UK) and SGS (HK).

As Medical Device 

  • Splash Resistance (Synthetic Blood Penetration) ASTM F1862

  • Bacterial Filtration Efficiency (BFE) - ASTM F2101

  • Differential Pressure(delta-P) (Breathability) - ASTM F1862

  • Microbial Cleanless (Biorburden) – ISO 11737 -1 

  • Biocompatibility – ISO 10993

As Respirator  - Personal Protective Equipment (PPE) 

  • Filtration Efficiency (NaCl aerosol test - N) 

  • Filtration Efficiency (Paraffin Oil aerosol test – P/R) 

  • Breathing Resistance (Inhalation) 

  • Breathing Resistance (Exhalation)

  • Practical Performance (Compatibility with skin / no mask movement)

  • Total Inward Leakage (Face Sealing Fit Test)

  • Carbon Dioxide Content of Inhalation Air (Dead Space Test)

  • Blood penetration resistance

  • Flammability

Tests carried out by SGS (HK)

  • Acute inhalation toxicity test

  • Acute oral toxicity test

  • Dermal irritation test

  • Toxicological risk assessment (TRA)

Additional tests carried out by Nelson Labs

  • Antibacterial test – 21 CFR 58 (Bacteria Killing)

  • Viral Filtration Efficiency (VFE) – ASTM F2101-07 

No, NASK NANOFIBER RESPIRATOR including the S-shape plastic clips are free from additional substances such as preservatives, disinfectants, herbal substances, preparations or other soluble chemicals, substances of animal and human origins. All materials are latex-free. 

The manufacturing premises are located in Hong Kong. NASK NANOFIBER RESPIRATORS are manufactured under controlled clean-room conditions, free from dust including temperature and humidity control.

Yes, NASK makes mention of the LOT number, manufacturing and expiry dates on both the box and the individual packaging. 

Usage, Storage and Disposal

Even though NASK NANOFIBER RESPIRATOR has superior filtration efficiency with trapping virus and killing-bacteria properties, users are advised to combine hand hygiene with any time they touch their respirator or face, as well as before putting and after taking them off.

We need to differentiate between fit testing and seal checking. 

Fit testing helps assure that the respirator fits and seal properly so potentially contaminated air cannot leak into the respirator and hazardous substances are kept out. Once the fit test is passed successfully NASK NANOFIBER RESPIRATOR can be used. 

A seal check is a quick check performed by the wearer each time the mask is put on. It determines if the mask is properly seated to the face or if it needs to be readjusted. It is not a substitute for a fit test. 

Users are advised to view the donning & doffing video instruction as well as to read and understand instructions for use included in the packaging. 

2 S-shapes plastic clips are provided with NASK NANOFIBER RESPIRATOR to provide several locking positions for matching with different head sizes. They allow to adjust the fitting for optimal sealing. Users are advised to view the donning & doffing video instruction to make best use of the clips.

The high level of breathability in combination with the superior loading capacity and the good resistance to moisture allow NASK NANOFIBER RESPIRATOR to be used continuously for 8 hours or longer. If the respirator becomes damaged, soiled or breathing becomes difficult, users are advised to leave the contaminated area immediately and replace the respirator. As a general rule, users are advised to view the donning & doffing video instruction as well as to read and understand instructions for use included in the packaging.  

As an FFP2 NR  (Not Reusable) , the use of the NASK NANOFIBER RESPIRATOR   is limited to one working day. Evidence on the impact of the re-use of disposable single-use surgical masks and respirators is very limited. However, extended use is favored over re-use because of reduced risk of contact transmission. Such practices should only be considered in situation of critical shortage. 

NASK NANOFIBER RESPIRATORS must not touch one another to avoid cross-contamination. Hang used respirators marked with your name in designated storage area or store in the bag provided with the respirator or a box marked with your name. Storage containers should be disposed of or cleaned regularly.

NASK NANOFIBER RESPIRATOR is not designed to be washed, heated-up or UV-light treated. By doing so, the electro charge would be destroyed, thus affecting the filtration efficiency and therefore, the level of protection

The shelf life of NASK NANOFIBER RESPIRATOR is 3 years from the date of manufacture. The bacterial killing function shows as 5 years efficacy. However, we do not recommend to use it after expiry date is reached.

It is recommended to wash hands before taking off NASK NANOFIBER RESPIRATOR. If possible, only elastic ear-bands and clips should be touched when taking it off. It is advised to place the respirator in the individual bag, tied firmly and to dispose either in a garbage bin with lid designed for used materials or with general household waste. In case of confirmed contamination, it is appropriate to write Risk of Contamination on the bag. Finally, you are advised to wash hands with soap and water.