... , rotary bit, TCI tricone bit, PDC drill bit , diamond core bit, bicenter bit, single cone bit , reamer bit, down hole opener, hole enlarger, drag bit, button bit and drilling equipment ... bit, 4-wings drag bit optional. Shapes can do chevron & step as requested. Sizes: 3 3/4", 3.7/8", 4", 41/4", 55/8 ", 47/8", 6", 7.3/8", 4.3/4 ...