The TandemKross Shock Block Bolt Buffer accessory is a must have for any owner. The TANDEMKROSS Shock Block Bolt Buffer is a great upgrade and is an inexpensive addition to your rifle. Eliminates the metal-to-metal contact between the bolt and the receiver pin and eliminates vibration cause by the metal-to-metal contact. The Shock Block Bolt Buffer for reduces impact stress on the receiver, made for high tolerances, high impact resistance, superior load bearing properties. FeaturesEliminates "Bolt-Battering" of the receiver Eliminates vibration from metal to metal contact Easy drop in ready, no tools required