THE BCM(R) MK2 BUFFER MOD1 - T1, Intermediate Length (BUFFER ONLY) (weight = approximately 4.7oz) 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 Uses a M16A4 rifle spring with more spring coils than M4 carbine, increases consistency and widens operating envelope Internal spring to reduce noise of counter weight shifting and ensure more consistent weight placement Made of 7075T6 aluminum, hard coat anodized for lasting endurance. Comprised of Mil-Spec components BCM US Patent #10415907 IMPORTANT NOTE: MK2 MOD 1 buffer series is to ONLY be used on the AR15 receiver platform and it ONLY works in conjunction with the BCM MK2 Receiver Extension (BCM part #BCM-MK2-RE) and the Mil-Spec Rifle M16 Action Spring (BCM part # SPRING-RIFLE-M16-ACTION). To use any other component, not specifically developed to function with the MK2 MOD1 Intermediate Buffer can cause damage to the weapon and possibly injure the operator.