Eclipse E20-4 Heavy Duty G-Clamp 4 Inch / 100mm  The Eclipse E20-4 has a whopping clamping force of 545kg (1200lbs). Its guaranteed unbreakable malleable iron frame with a fast action twin start rolled acme thread makes this model well and truly up to the task. The steel swivel shoe applies an even pressure, even on angled surfaces, whilst the tommy bar will bend before the frame can become over-stressed.  Features:   Acme thread  Steel swivel shoe  Guaranteed unbreakable for long-lasting use Malleable iron frame Specification:  Clamping Capacity: 4\" (100mm)  Frame Proof Loads: 1200lbs / 545kg  Weight: 1.5kg