Super hard coating reduces friction and heat build-up, lasts longer than standard drills Surface drills cooler, lessens torque and downward drilling pressure All sizes 3/16 in. and larger have 3 flats on the shank for a better grip on the drill bit All sizes 13/32 in. and above have a 3/8 in. reduced shank The 135 degree split point eliminates the need for a center punch and keeps the drill from skating on the hard materials Includes (1) one each: 1/16 in., 5/64 in., 3/32 in., 7/64 in., 1/8 in., 9/64 in., 5/32 in., 11/64 in., 3/16 in.,13/16 in., 7/32 in., 15/64 in., 1/4 in., 17/64 in., 9/32 in., 19/64 in., 5/16 in., 21/64 in., 11/32 in., 23/64 in., 3/8 in. and metal case with pilfer proof tab.