Professional for jewelry maker, used with pneumatic impact engraving machine, air hand graver Made of strong hard steel,not easy to bend and break. with higher wear resistance and higher efficiency Shank: 3mm, Length 45mm, shapes: 30º/45º/60º/75º/90º/105º/120º, total 7 pieces High concentricty and high speed, the bit can cut clean without any ragged edges, High and convenient to use, practical accessory for jewelry processing, Manufacturer: Akfldms