National Hardware G3032BC Double Bolt Snaps for quick attachment at both ends. Aluminum body and steel spring. Designed to use with rope, chain, strap, animal leashes and other home, farm, and recreational applications. Easy bolt retraction with pull down trigger. Size: 3-15/16" Finish: Nickel Double bolt snap Aluminum body and steel spring Designed for quick attachment of gear, keys, tools, and other equipment.