Stock up with this Filtering Silicone Seal Face Cover with Replacement Filters Get one cover with a choice of 10, 20 or 30 replacement filters, or get 50 filters on their own This cover has a silicone seal that acts as a suction cup around the nose and mouth More effective than your average surgical cover Each filter has 3 layers which have their own filtering purpose: Inner layer (closest to face): absorbs hot air from the body and keeps skin dry Middle layer: filters non-oily particles from the air Outer layer: built to catch droplets and bigger particles Layer over the filters has 21 bars allowing you to breathe normally Fits securely and comfortably around the head with the elastic strap Stands up to temperatures from -40 to 220 degrees celsius Buying Options: 17.99 pounds for 1 cover and 10 filters 23.99 pounds for 1 cover and 20 filters 29.99 pounds for 1 cover and 30 filters 35.99 pounds for 50 filters