Yankee Hill Machine Co Suppressor Gas Block, .750 Diameter, Phosphate Finish, Black YHM-9389-SS YHM's suppressor gas block is designed for customers looking for an affordable way to tune their AR for shooting suppressed. This gas block features a gas port hole that's 50% smaller than a standard gas block. This reduced gas port decreases "port pop" and mitigates blowback to the shooter" making shooting suppressed much more enjoyable. Due to variations in barrel gas port size" barrel length" caliber" suppressor design" ammunition" etc." this item may require the customer to fine-tune the port size to match their exact setup. It is designed to be used on a host firearm that will be shot exclusively with a suppressor attached.