All brakes are made from 416 stainless steel.
The brakes come ready for .17 caliber, anything larger must be opened up by a competent gunsmith. They come in two sizes:
- 3/4″ w a 1/2×28 thread, brake can be turned down to .630″
- 1″ w a 5/8×24 thread, brake can be turned down to .750″