The Kaw Valley Precision Plan B Taper Mount Brake is seamlessly engineered to be fully compatible with Plan B mounting systems. Designed to effortlessly attach and detach from your firearm, our brake ensures quick and hassle-free adjustments to your shooting setup without the need for timing or shims. The KVP Plan B Taper Mount Brakes are compatible with all Plan B adapters on the market to include the Rearden Atlas, Diligent Defense Zilch, and many others. Features17-4 Stainless Steel MaterialBlack Nitride QPQ FinishOAL: 1.27"Bore: .500 (ANY Caliber)Shoulder: Square