ZAGO's sealing washers are composed of a stainless-steel type 316 inner component. This inner component is encompassed by molded silicone rubber, which creates an impenetrable, air-tight seal. In addition to being pressure resistant, ZAGO pressure sealing washers provide excellent noise and vibration reduction. They are reusable, highly durable and engineered to withstand extreme temperatures and weather conditions. ZAGO pressure sealing washers are RoHS and REACH compliant and made in the U.S.A.