Riflespeed RS7543 AR15/AR10 Gas Control Assembly, 0.750 diameter. Adjustable gas flow with a knob, no tools required. The control knob is numbered to show current setting, and you can quickly return to a previous setting. It features two rotation ranges (1-12) and multiple plunger sizes to accommodate various cartridges. The patented Rotation Stop helps prevent accidental disassembly. Engineered for military and law enforcement duty use, it improves reliability, reduces recoil and muzzle rise, and can be optimized for light commercial ammo or mil-spec rounds. Note: Requires Riflespeed straight gas tubes.