Precision Reflex Picatinny Railed Gas Block .875 Diameter Black. This gas block weighs 2.5oz. The block locks into place with 2 crossbolts the same as our original gas block front sight. The rail height from barrel center line is 1.328 inches. The rail Length is 2.5in The Gas block comes with a .030 ring spacer and roll pin for gas tube. Specifications for Precision Reflex Picatinny Railed Gas Blocks: Manufacturer: Precision Reflex Color: Black Fabric/Material: Aluminum Gun Make: AR Platform Weight: 2.5 oz Condition: New Height: 1.328 in Finish: Hard Coat Anodized Length: 2.5 in Features of Precision Reflex Picatinny Railed Gas Block: The rail is constructed of lightweight T6 6061 hard coat Black anodized aluminum This gas block weighs 2.5oz The block locks into place with 2 crossbolts the same as our original gas block front sight The rail height from barrel center line is 1.328 inches The rail Length is 2.5" The Gas block comes with a .030 ring spacer and roll pin for gas tube. Package Contents: Precision Reflex Picatinny Railed Gas Blocks Precision Reflex 03-875-04: Picatinny Railed Gas Block .875 Diameter Black