SADLAK Gas Cylinder Wrench OD Green. The large hole in the wrench has an internal D-shape that holds the piston from rotating without causing any damage. Specifications for SADLAK Gas Cylinder Wrench: Manufacturer: SADLAK Fabric/Material: Steel Color: OD Green Finish: Powder Coated Gun Model: M14 Springfield Armory M1A Length: 0.75 in Caliber: .308 Winchester Gun Type: Rifle Features of SADLAK Gas Cylinder Wrench The gas cylinder wrench can be used to conveniently hold the small end of the piston during cleaning. The large hole in the wrench has an internal D-shape that holds the piston from rotating without causing any damage. Package Contents: SADLAK Gas Cylinder Wrench What firearm models does the manufacturer say SADLAK Gas Cylinder Wrench is compatible with? The manufacturer suggests that SADLAK Gas Cylinder Wrench is compatible with Springfield Armory M1A M14SADLAK 140100: Gas Cylinder Wrench OD Green