Electroplated Counter Strike Tools are designed for Countersinking operation in materials such as PVC, Granite, Linings, Rubber, Glass, Quartz, Composites, Graphite Epoxy, Carbon, Boron, Fiberglass, Marble and many other materials. Designed for use on hole diameters from 1.5″ (38.1mm) to 2.5″ (63.5mm).