These PH2x25mm drywall dimpler countersink bits are supplied as a set of 10 inside a plastic storage box. They are made from S2 steel alloy, which is designed to resist damage through its shock resistant qualities. Depth stop limits the screw penetration and damage to the plasterboard. Their use offers the easiest and most effective way to install drywall screws into plasterboard, plywood and other similar materials.