A combination of basalt, amorphous silica, and aluminized silica joined together with stainless steel thread to create the full auto rated Liberty's Defense staightJacket Thermal Attenuator, which provides absolute flame resistance and heat mitigation for direct contact with your silencer's extreme continuous temperatures up to 2000°f and short excursions of 3,000°f. Due to an overwhelming surge of orders our current lead time is approximately one month.