Fein 64298050000 Imperial Twist Drill KitFein 64298050000 The drill bits in these sets have a black oxide finish that retains lubricants to improve the bits' wear resistance and chip flow. Black oxide bits should only be used for drilling ferrous metals. High speed steel drill bits provide some flexibility and absorb some shock and vibration. Drill Bit Sizes Included 1 4 in; 5 16 in; 3 8 in; 7 16 in Smallest Drill Bit Size 1 4 in Drill Bit Point Angle1 35 Includes 1 4 in, 5 16 in, 3 8 in, 7