I have a different but even more wonderful screwdriver. Picture a flat disc, about the size of a quarter, but thick, approx. 3/8" . Imbedded in the bottom is a blade that fits into the screw. The top has an indentation to place a finger while you use the other hand to turn the "disc". This cannot slip off because it is held on with your finger. That is probably a terrible word picture. Google Morko Products. for a picture of their throat plate screwdriver.