This is the BNC Female Dust Cap with chain. It features a BNC Female connector on one end, and ball bearing chain on the other. The cap and chain are made with a nickel-plated, metal construction for maximum strength and durability. The cap will allow you to prevent any dust, water, or moisture from being seeped in. That could cause interference, or power loss. The BNC Female dust Cap with chain is a quick and easy solution for your cabling projects. For more information on our products, please contact our customer service department at 888-519-9505. For all your cable and connector needs, choose Show Me Cables.