1.16'' 406.4mm SKH537 TCI drilling bits 2.material:tungsten carbide 3.Strong resistance to abrasion ... heel rows and inner rows. This design provides a fast drilling rate and added cutting structure durability in medium-to-midium ... bits, tricone bits, steel PDC bits, drill bits, TCI bits,drilling bits, oilfield bits, steel tooth bits,drag bits, hammer bits ...