The Jorgensen POJ3712 bar clamps are seriously strong and are made using high quality materials for lasting value and great performance. The high-carbon, rust-resistant steel bar packs a whopping 100,000 pounds per square inch of tensile strength. The fast-acting sliding head is acme threaded to accommodate a cold-drawn steel screw with a large easy-grip handle and swivel pad. The original multiple-disc-clutch design allows the sliding head to hold securely at any point along the bar. These clamps are available in a wide variety of sizes and clamping forces for light-duty, medium-duty, and heavy-duty applications.