1)About the drill bit, the cutting depth includes: 30mm , 55mm , 75mm , 110mm. 2)Material: ... cutter) and special drillsDetail description about our annular cutters1)Max.drilling depth:30mm/55mm/75mm/110mm2)Material:HSS9341, M2,M35,M423 ... , airplane manufacturing and gas pipeline industries.5)The effective of drilling is much better and quicker than the common drill bits ...