The NSI G-1-SDB Heavy Duty Bronze Ground Clamp for Direct Burial grips on pipes between 1/2" to 1" in diameter and is suitable for direct burial applications. The 304 stainless steel screws and cast bronze clamp body are made of economical, high-quality metals that provide durable performance in a range of applications. UL Listed 467 for Grounding and Bonding. Stock products you can rely on—stock NSI.