
Details
Each mask uses a replaceable 4-ply filter that has been tested to block microparticles at over 98% efficiency. Our filters are custom-fitted to the G-Series Masks and should be replaced after 32 hours of use. Order these in different quantity packs to fit your needs.
Product Features
Disclaimer: In no event shall CastleGrade™ be liable for any direct, indirect, punitive, incidental, special consequential damages, to property or life, whatsoever arising out of or connected with the use or misuse of our products.
Please Note: No respirator can protect 100% against COVID-19 or other viruses. COVID-19 is not yet fully understood. We cannot and do not guarantee that our respirators will protect you against the Coronavirus.

Replaceable Filters
4 Protective Layers
Each G-Series Mask uses a replaceable 4-ply filter that has been tested to block microparticles at over 95% efficacy. The mask has no valves. Air is filtered in 2 directions, on both inhale and exhale.
Our filters are custom-fitted to the G-Series Masks and should be replaced either weekly or after 32 hours of direct use. When in use, the filter's blue side (PP Meltblown) should be facing in towards you.
Nelson Labs USA (8.13.20)
Passed NaCl test
Average across 20 tests
Filtration Efficiency
98% Filtration
Must be 95% or greater
Particle Penetration
< 2% Penetration
Must be 5% or less
Protects against Smoke
Charcoal Filters
Introducing our activated carbon filters that aid in removing toxins from smoke and fumes. These 4-ply filters have been lab tested to show over 98% filtration efficiency with less than 1% particle penetration.

Customer Reviews
Registrations

Official Registration
View RegistrationTravel Compliance
Print Letter
Provisional Patent
U.S. Patent & Trademark OfficeEntrepreneur and business owner Anna Grinvald invented an earlier version of the G-Series in December. Anna’s mother lives in a senior care center in Israel and complained about how typical masks were fogging up her glasses. Ron Grinvald, a former injection mold specialist for several parts on the NASA spacesuit worked with Anna and eventually Dan Castle, owner of Castle Brand Group to improve it. The G-Series has recently been tested by the FDA, Nelson Labs, Alpha Labs and SMQ Labs and has performed extraordinarily well.
Yes, click here to view our registration on the official FDA website.
The G-Series filter has been lab tested by several third-party labs. Results from these tests have shown a level of filtration efficiency over 95% consistently, with Nelson Labs performing the Bacterial Filtration Efficiency (BFE) test which returned a 99.8% efficiency score. (N95 Masks are 95% BFE)
The G-Series Mask has been tested by several third party labs. Please click on the Science tab to learn more.
As a standard, we recommend purchasing the G9 size. The G8 size is recommended for teenagers and women with small head and face features (70pct of women prefer G9).
Remove the 4-ply filter and place it in the dishwasher. You can also submerge it in boiling water for 2 seconds. If you prefer to keep it clean throughout the day you can wipe it down with any disinfectant.
You can wear the mask for up to 1 week or 32 hours of direct use, before replacing the filter.
Wearing a high protective, silicone mask will slightly alter / muffle the sound of your voice.
We manufacture in several countries including Vietnam, Czech Republic, Germany and China.
Don’t! Keep the mask and buy replacement filters on our website when you are running low or sign up for the subscription so you never run out. We cringe seeing so many masks being discarded after just one day of usage and Mother Nature needs your help.
For safety purposes, once the product has shipped, we consider the respirator mask unfit for use by another customer. Thank you for understanding.