With AirAid's Replacement Air Filters you know you are getting the absolute best filter you can buy. They are made from the best materials available, utilizing a urethane body that won't curl or crack. AirAid also implements their SynthaFlow layer along with multiple cotton gauze layers for optimal filtration. By using the best materials, AirAid is able to offer a Lifetime "No Hassle" Warranty and are 100% reusable.