For rotary or percussion drilling. Chrome vanadium steel shank, diamond ground tip, special negative back grinding enables tip to bore through brick, concrete, masonry, ceramic tile, fiberglass, plexiglass, glass, cast metals, hardened steel, granite, marble, woods and plastic with a filing action. High tech bonding allows bit to withstand drilling temperatures up to 2000 deg F. Easy to resharpen. Includes one 1/8 in, 3/16 in, 1/4 in, 5/16 in and 3/8 in and plastic case. NOTE: Not recommended for use on mild steel. This includes aluminum, angle iron, copper, galvanized pipe, brass and stainless steel. Packaged in a plastic case.