1This is a straight shank twist drill set with incisive cutting and fast chip removal resistance 2Using HSS material, high hardness, good wear resistance 3This straight shank twist drill can be used for jasper, agate, pearl, and pebbles 4Can be used with worktop drills, electric drills, electric grinders and hole punches 5Suitable for printed circuit board, thin aluminum or iron plate, thin wood, plastic or other small objects processing