Pack of 30 unisex adult double valve filters with adaptable activated carbon to effectively filter fine particles from the ambient air. Soft and breathable, hypoallergenic and comfortable. Compatible with most standard size reusable and washable masks with filter pockets. Its high-efficiency filtration system, with an additional layer of melt-blown fabric, provides a better sterilization effect. The filter measures 14 x 10 cm. Does not include the mask. Lightweight and foldable 3D design, more comfortable to wear. Made of non-woven fabric. Made of high-quality, hypoallergenic melt-blown cotton, activated carbon fabric and submicron fiber, it provides 5 layers of multiple protection and good ventilation. Suitable for public places, workplaces, schools, offices, home cleaning and other jobs, restaurants, hair and nail salons, pet shops and other businesses, as well as indoor and outdoor activities. Easy to use: Place a filter in the back pocket of the mask for added protection. Replace