Bought these to fix up some vinyl plank flooring that has a couple gaps, they seem to stick well on a clean surface. That's the key, a clean suction cup and a clean surface to attach to. It also helps to push the suction cup into the surface your attaching to as you flip the clamping toggles. They have plenty of power to pick up shower glass, mirrors or hold on to a vinyl plank while you tap the handle with a mallet to close gaps.