The 0.3 air valve and magic 1 second cutter was developed to easily attach the air valve to a variety of other masks I use (disposable masks, cloth masks, cotton masks, filter replacement masks, fashion masks, etc.). ★Magic 1 Second Cutter: Patent Pending: (Korea, International PCT) 0.3 Air Valve: Design Registration Pending: (Korea) 1 second cutter is the leading leader. We designed this knife to be easy to get and easy to replace, so everyone can use the blade of a stationery cutter knife that is commonly used. Everyone can easily create clean round holes. Store the blade for safe storage during or after use. ★NOTE: 1 second cutter does not include the blade. Use your own utility knife blade. 0.3 air valve that can be used repeatedly for various masks in any position; Compact size with a diameter of 0.8 inch (21 mm) and height of 0.4 inch (9 mm) Easy to install, completely separate and washable for hygienic, ultra-slim 0.01 inch (0.3 mm) silicone valve membrane.