Quick and easy interchangeable mouth system for multiple applications Hollow mouth instrument and sharp cuts used for drilling. It allows with a single hammer blow on a variety of materials to drill circularly and with different diameters. Ergonomic handle: It absorbs a large amount of the impacts that are transmitted to the hand. Display field improvement. Content of the set of 15 measures, from 3mm to 30mm Ø, (increasing from 2mm from 4mm to 30mm Ø). Polypropylene case resistant to chemicals and shock.