Apart from your sash clamps falling over, the other infuriating thing is that clamping blocks never, ever seem to stay where they’re put. No matter how hard you try, they slip and slide about...even three hands aren’t sometimes enough to hold the things in place. By making our rare earth clamping blocks, unwarranted slippage is a thing of the past. They’ll stick to any ferrous surface, even one that’s upside down.