Forward Controls Design Gas Block Utility for Gas Tube Pinning and Gas Block Pinning Silver GBU Gas Block Utility. Machined from a solid block of 6061 it's 3.35in (L) x 2.45in (W) x 0.94 (H) it weighs 7.52 oz. GBU's circular lines below and rough texture inside the gas block cavity are by design lest anyone should think they're tool marks these take machining time to put in place. Whereas it would have been good enough to have consistent surface throughout the GBU exterior we put in thoughtful and useful touches. The textures are one of them the other is the finger access relief access above and below the gas block cavity. NOTE: GBU is compatible with low profile gas blocks. It is incompatible with TDP spec front sight post/gas blocks or any adjustable gas blocks. GBU may be incompatible with gas blocks that use a tapered pin. Specifications for Forward Controls Design Gas Block Utility for Gas Tube Pinning and Gas Block Pinning: Manufacturer: Forward Controls Design Color: Silver Weight: 7.52 oz Width: 2.45 in Length: 3.35 in Height: 0.94 in Features of Forward Controls Design Gas Block Utility for Gas Tube Pinning and Gas Block Pinning Rebated bottom for using a vise to secure the platform Textured bottom to limit sliding on the workbench Textured gas block cavity to reduce gas block movement inside the GBU Blind hole slot to capture gas tube pin Wide gas block cavity allows gas blocks up to 1.19in long (Crane spec gas blocks are 1in long.) Gas block cavity is bi-directional i.e. barrel with gas block and gas tube can be seated on GBU with the muzzle facing left or right. Left side accommodates gas blocks with barrels diameter up to 0.855. Right side barrel cavity is smaller and accommodates barrels up to 0.760 diameter. Package Contents: Forward Controls Design Gas Block Utility for Gas Tube Pinning and Gas Block Pinning Forward Controls Design GBU Gas Block Utility: Gas Block Utility for Gas Tube Pinning and Gas Block Pinning Silver