The CMMG Fastback Receiver Extension allows you to deploy your favorite stock (or brace) faster than ever. The Fastback Receiver Extension attaches to any firearm that accepts a Mil-Spec receiver extension (buffer tube). Once installed, this allows you to easily pull the stock (or brace) back to an extended position, without pressing a release button. Fastback Technology is a Patent Pending feature on certain receiver extensions that makes the RipStock and RipBrace instantly deployable and allows you to simply pull straight back to extend the stock or brace. No locking tabs to bind when dirty and no release lever like most extendable stocks and braces. The Personal Position Preset, P3, offers multiple customizable length presets to ensure the stock or brace extends to your personal position every time it is deployed. Simply adjust the indexing screw into one of the holes to customize your preset. Features Mil-Spec DiameterAluminumHard Coat Anodized FinishP3 Screw Included