The NSI GCA-4 Aluminum Ground Clamp for 250 MCM to 6 AWG Aluminum and Copper Cables grips on water pipes, galvanized pipe or steel conduit between 2-1/2″ to 4″ IPS pipes. The high-strength extruded aluminum alloy design is plated to provide low-contact resistance and features zinc-plated steel set screws for long-term installation. Use this adjustable clamp to ground copper or aluminum cables to pipes and conduit in indoor environments. UL Listed 467 for Grounding and Bonding. Stock products you can rely on—stock NSI.