This kit contains all the necessary parts to mount to your Mil-Spec dimension stock assembly to your Mil-Spec lower receiver. Lessens felt recoil, without compromising reliability Provides a more consistent carrier velocity, which can aid in accuracy, reliability over conventional carbine buffer system Increased internal counterweight travel reduces bolt bounce Internal spring to reduce noise of counterweight shifting and ensure more consistent weight placement Mil-Spec M16A4 rifle spring with more spring coils than M4 carbine, increases consistency and widens operating envelope Buffer made of 7075-T6 aluminum; hard coat anodized for lasting endurance Mfg: Bravo Company