At a Glance: Eliminates "Bolt-Battering" of the receiver Eliminates vibration from metal to metal contact Easy drop in ready, no tools required Oil and solvent resistant This accessory is a must have for any RugerA(R) 10/22A(R) owner. The TANDEMKROSS "Shock Block" Bolt Buffer is an great upgrade and is an inexpensive addition to your 10/22A(R) 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 TANDEMKROSS "Shock Block" Bolt Buffer reduces impact stress on the receiver, made for high tolerances, high impact resistance, super Mfg: Tandemkross