Works perfectly, giving you the confidence to move your pane of glass into place, safely. I used the sucker for moving large panes of glass for my new greenhouse roof. One point I should make, however, is that I did not realise that you have to depress the long button several times until you become aware of resistance and then you can't depress it any longer (My son worked it out for me). At that point the glass is ready to move. When the glass is in position the lever at the other end is depressed to release the sucker from the glass.