1)Bits size range :3-3/5"-26" 2)Best quality and low price 3)Longer drilling intervals 4) API &IADC 1)Bits size range :3-3/5"-26"2)Best quality ... cone-dropping to minimum.Main Type AvailableSize: 8 1/2",9 1/2",9 5/8",9 7/8",10 5/8",12 1/4", etc. IADC ... cone Cdropping to minimum.Main Type AvailableSize: 2 3/8",3",3 5/8:",3 7/8",4",4 1/2",4 5/8",4 3/4",6",6 1/2 ...