Precision Reflex AR-15 Gas Block Fixture w/Roll Pin Starter Punch White/Black Black. The block holds the gas block to allow the roll pin starter punch to start the roll pin. Specifications for Precision Reflex Gas Block Fixture w/Roll Pin Starter Punch: Manufacturer: Precision Reflex Color: White/Black Fabric/Material: Nylon/Steel Gun Model: AR-15 Package Contents: Precision Reflex Gas Block Fixture w/Roll Pin Starter Punch What firearm models does the manufacturer say Precision Reflex Gas Block Fixture w/Roll Pin Starter Punch is compatible with? The manufacturer says that Precision Reflex Gas Block Fixture w/Roll Pin Starter Punch is compatible with AR-15Precision Reflex 05-100: AR-15 Gas Block Fixture w/Roll Pin Starter Punch White/Black Black