The NSI G-13 Heavy Duty Bronze Water Pipe Ground Clamp grips on water pipes between 4-1/2" to 6"with its serrated body. The zinc-plated steel screws and cast bronze clamp body are made of economical, high-quality metals that provide durable performance in a range of applications. Use this clamp to quickly and easily ground wires to water pipes with the included set screw. Designed for use alone or with heavy-duty bronze adapters. cULus Listed 467 for Grounding and Bonding. Stock products you can rely on—stock NSI.