These clamps are all plastic so the clamping force is limited. They are good for positioning parts for drilling holes, driving rods with a pneumatic nailer, clamping work pieces for sawing on a boom or crosscut saw, gluing some parts, and similar tasks. "Quick Controller" really saves time. With this function, it takes about one second to open and close the clamp. I would give 5 stars if these clamps were steel.