Black oxide bits provide longer life and faster drill times, parabolic flute, clears chips faster, 135 degree split point, precision start no walking, 3-flat secure grip shank, reduces bit slipping in chuck and a reduced shank diameter foruse in 3/8" chucks. Set includes: (1) 1/16", (1) 5/64", (1) 3/32", (1) 7/64", (1) 1/8", (1) 9/64", (1) 5/32", (1) 11/64", (1) 3/16", (1) 13/64", (1) 7/32", (1) 1/4", (1) 9/32", (1) 5/16", (1) 3/8" and a plastic case.