These heavy-duty bar clamps are made from strong and durable engineering grade plastic. They are capable of evenly distributing up to 306kg of sustained clamping force. The robust I-Beam structure and C45 rail reduces unwanted bending. The TPU protective cushions safeguard the workpiece from marking and damage. One-handed operation is easy, thanks to the quick release trigger. There is also a quick change button to convert the clamp to a spreader. They are designed with long handles to enable better leverage for reaching higher pressure easily.