The steel-reinforced jaws and thick steel I-beam bar did not flex under pressure. But at 6-1/2 lbs for the 24" clamps and 9 lbs for each 48" model, the heft adds up when you move a clamped assembly off your bench. The movable jaws dig into the smooth bars when tightened, leaving bite marks that impede movement on later glue-ups. And the fine handle threads require more turns to tighten and loosen than most other parallel-jaw clamps.