How do we care for the mask? 

Hand wash with cool water or soap only. Use of laundry/ dish detergent or any chemical cleaning product is not recommended. Line dry or under the sun after washing. *Do not bleach/ iron/ dry clean/ tumble dry. 

Please check our Instagram @greensisterscreation for a washing instructions on the highlight section. 

Alternatively, here's the link

What is the difference between a pocket insert and without?

There is an option with and without pocket to insert filter. The main difference is that the mask without pocket insert will be much more lightweight and breathable. I would recommend this option for summer, and for those who might not use the mask after 100 washes. The efficiency of the mask is not affected. As the mask is 99% BFE effective and up to ASTM F2100 standards for 100 washes, there is no need for insert. Only people with high risk like doctors would require an insert filter. And yes, if you use an insert filter, those need to be replaced daily and we do not supply those as everyone's requirements are different. Although many do not mind the pocket version, a small minority of our customers find that the loose fabric of the pocket opening will stick to their face when breathing. 

What are the materials made of? 

The shell fabric is made of 100% water-resistant polyester. Middle layer is a non-woven cloth with PE breathable coating, a type of recycled 100% polyester that is the same material of a hazard gown. The inner lining is a Japanese medi fabric that is anti-viral and anti-bacterial. 


What is the ASTM F2100 standard?

ASTM standards are referenced by the Food and Drug Administration (FDA), as the endorsed standard in the United States. 

BFE (Bacterial Filtration Efficiency): BFE measures how well the medical face mask filters out bacteria when challenged with a bacteria-containing aerosol. ASTM specifies testing with a droplet size of 3.0 microns containing Staph. Aureus (average size 0.6-0.8 microns). In order to be called a medical/surgical mask, a minimum 95% filtration rate is required. Moderate and high protection masks must have bacterial filtration rates greater than 98%.

Ours is 99% BFE.

Fluid Resistance: Fluid resistance reflects the surgical mask’s ability to minimize the amount of fluid that could transfer from the outer layers through to the inner layer as the result of a splash or spray. ASTM specifies testing with synthetic blood at pressures of 80, 120, or 160 mm Hg to qualify for low, medium, or high fluid resistance. We are tested to be 120 mm Hg. 

What tests or ratings should I rely on to ensure my mask is safe?

Specifications developed by the American Society of Testing and Materials (ASTM) are generally accepted as the industry standard. Beware of mask ratings that do not follow ASTM guidelines. Some manufacturers may refer to “filtration rates” or the “number of layers” as an indication of effectiveness. These vendors may not be adhering to the ASTM standards and should be questioned for specific test data.

How many times can we use the mask to ensure its effectiveness?

The mask will remain its effectiveness up to 100 washes. 



We ship worldwide but when you buy 5 masks, we offer free shipping to many countries. 

The shipping rate is the same for 1 mask up to 4 masks. So the more you buy, or can consolidate your order with friends and family, the better. Free shipping to the US, UK, Canada, Australia, New Zealand, Malaysia and within Hong Kong for 5 masks and above. 

3. Why is there a no return policy for masks?

The only reason being is a hygiene reason. If however, you can prove to us within a few days of receiving the mask that it is defective, we will replace it. 

What happens if the shipment is confiscated at customs?

Due to the COVID-19 global traffic suspension, we are only choosing expedited courier service so that it will avoid a lot of these problems. If however, we are unlucky and the package is still detained at customs and unretrievable, we will bear half the cost of the order excluding the shipping costs. 

When do I expect to receive the masks after I placed my order? 

Normally 3 to 5 business days for Hong Kong orders and 10 to 14 business days for international orders, subject to actual freight conditions between Hong Kong and destination. 

*** Please note that due to Covid delays and holiday season, there will be a slight delay in shipments. Every tier of our logistics are facing delays, but rest assured we will mail your package out as soon as we can. Especially in Canada where Covid cases are rising again, we are experiencing huge delays with Canada Post. Therefore, we have included a guaranteed express tracked shipping for ease of mind. Thank you ***