Samson Lightweight Low Profile Gas Block .625 Diameter Black. That's why we designed our Lightweight Low-Profile gas block to be as light as possible yet strong enough for serious use. This product is precision machined in our New Hampshire factory. Attaches to the barrel with a clamp screw. Specifications for Samson Lightweight Low Profile Gas Block: Manufacturer: Samson Color: Black Features of Samson Lightweight Low Profile Gas Block Low-profile lightweight design For .625" diameter barrels Package Contents: Samson Lightweight Low Profile Gas Block Samson 04-06025-13: Lightweight Low Profile Gas Block .625 Diameter Black