Troy Ind SGASA4L00BT00 Low Profile Gas Block SGASA4L00BT00 Steel .750"
The .750 Low-Profile Gas Block is made for rail systems that need to go over the gass block. Fits all M4 carbines and M16A2, A3 & A4 rifles. It is machined from hardened steel with a black oxide fiinish and are made in the U.S.A..