CMC Triggers AR-15 Low Profile Gas Block .750 Nitride Finish Black. Especially helpful in customizing short-barreled tactical rifles. Designed Specifically for AR15 s with a barrel .750" O.D. at gas port. Low Profile version is a low and narrow one-piece block designed to fit inside most free-float hand guards; allows use of rifle length forearms on carbine length barrels for a clean streamlined look and added gripping surface. Securely attaches to the barrel with included dual hex head set-screws. Works in conjunction with all CMC Triggers AR-15 Nitride Gas Tubes or standard Mil Spec gas tubes and hardware. Specifications for CMC Triggers AR-15 Low Profile .750 Gas Block: Manufacturer: CMC Triggers Color: Black Fabric/Material: 17-4PH Stainless Steel Gas Block Journal Size-Diameter: .750 in Size: 1.35x1in Gun Model: AR-15 Weight: 0.66 oz Features of CMC Triggers AR-15 Low Profile .750 Gas Block: Machined from 17-4PH Stainless Steel Weight: 0.66 oz Dimensions: 1.35(ht) 1(ln) made in specialized factories Package Contents: CMC Triggers AR-15 Low Profile .750 Gas Block What firearm models does the manufacturer say CMC Triggers AR-15 Low Profile .750 Gas Block is compatible with? The manufacturer says that CMC Triggers AR-15 Low Profile .750 Gas Block is compatible with AR-15CMC Triggers 81611: AR-15 Low Profile Gas Block .750 Nitride Finish Black