Spikes Tactical Gas Block Micro .750 w/Two Set Screws. Specifications for Spikes Tactical ST Micro Rifle Gas Block: Manufacturer: Spikes Tactical Coating: Black Nitride Fabric/Material: Solid Billet Steel Gun Model: AR-15 Weight: 1.9 oz Additional Features: w/Two Set Screws Condition: New Country of Origin: USA Features of Spikes Tactical ST Micro Rifle Gas Block: 0.750 Low Profile Gas Block Solid Billet Steel .750 I.D. Black Nitride Coating Weight: 1.9oz 0.625 Low Profile Gas Block Solid Billet Steel .625 I.D. Black Nitride Coating Weight: 1.5oz Package Contents: Spikes Tactical ST Micro Rifle Gas Block What firearm models does the manufacturer say Spikes Tactical ST Micro Rifle Gas Block is compatible with? The manufacturer says that Spikes Tactical ST Micro Rifle Gas Block is compatible with AR-15Spikes Tactical SUGB120: Gas Block Micro .750 w/Two Set Screws