The POWERTEC 20318 Ductile-Iron Base, Push/Pull Quick-Release Toggle Clamp, 500 lb Capacity, 305-CM, (4PK). Delivers a rock-solid grip on your stock when your project requires a push/pull holding-action that locks your workpiece, flush and tight, against a positive stop. With its superior, vibration-resistant, ductile-iron base, you are assured the kind of stable stock placement that allows for optimal woodworking safety and efficacy. And because ductile iron has an enhanced capacity to stand up to (sustain, absorb) maximum tensile strength, you can depend upon the ultra-potent hold of these clamps in even your most demanding applications. Lastly, having greater yield strength than cast steel, this unique material gets top marks in durability and high-performance. The clamp body itself is ruggedly constructed of zinc-plated, cold-rolled carbon steel that resists corrosion, and is the industry-grade material of choice for clamping components. Featuring side clamping action that provides the unique ability to securely grip your workpiece in a vertical or horizontal position. Handle opens a full 180 degrees, so edge mount this device to your fixture or work surface to take advantage of the full clamping range. Last but not least, its ergonomic ribbed-plastic handle provides a comfortable, safe and sturdy grip that allows for enhanced user leverage and control.