The NSI G-20DB Heavy Duty Bronze Ground Clamp with Wire Adapters grips on pipes between 1/2" to 1" in diameter and features a special pressure bar for grasping cable armor thereby reducing the chances of grounding conductor being pulled out. The silicon bronze screws and bronze clamp body are made from tough, high-quality metals that provide durable performance in a range of applications. Use this clamp to connect 4, 6, or 8 STR ground wire to copper water pipe. UL Listed for direct burial in both earth and concrete and well as UL Listed 467 for Grounding and Bonding. Stock products you can rely on—stock NSI.