Our black & gold drill bits with a 1/2" reduced shank are made from the highest quality high-molybdenum steel and are nitro-carburized for hardness and long life. They feature a 135* split point which allows the bit to quickly sink into hard metals without "walking" eliminating the need for pilot drilling and a 1/2" reduced shank with flats on it to eliminate chuck slippage. These drill bits are great for drilling hardened steels and stainless steel and the black & gold coating provides lubricity when cutting. This set goes from 9/16"-1" by 16ths and has 8 pieces. Made in the USA by Norseman Drill & Tool.