Ultradyne Quantum Gas Block Adjustable .625in. Having a gas block adjusted precisely allows the bolt carrier group to cycle only hard enough to extract and feed the new round into the chamber without hammering hard against the receiver extension. The adjustability can easily improve the performance of any rifle but it is especially important for the competitive shooter or when using hotter ammo or a suppressor which sends significantly more gas rearward. The UD Gas Block allows for a smoother cleaner and cooler cycle which improves performance by leveling the feel of the shot and reducing recoil. This results in quicker more accurate follow up shots. A perfectly tuned UD Gas Block also neutralizes the increased gas pressure created by hot ammo and suppressors which minimizes wear and tear on a rifle and creates less fouling so your rifle continues to function flawlessly for years to come. Specifications for Ultradyne Quantum Gas Block: Manufacturer: Ultradyne Color: Black Coating: Salt Bath Nitride Fabric/Material: 416 Stainless Steel Package Contents: Ultradyne Quantum Gas Block Ultradyne UD12002: Quantum Gas Block Adjustable .625in