8 inch Max Drilling Diameter Our core drilling machine generates extreme power because of its 3980W copper motor Maximum Speed 750RPM Maximum Coring Diameter 8205 mm More importantly the 4.25"/108 mm core bit in the picture is included. Construction: As the machine will work upside down, so water would unavoidable flow on to the drill machine. In this case, our drilling rig has a rustproof steel forged output shaft and copper water inlet for a long-lasting water supply. Thoughtful Security Design: We also provide overload protection and an upgraded cooling . They are designed for avoiding burn-in and prolonging the service lifespan of the drilling press machine. Ergonomic Handle & Stable Base It features an ergonomic handle and large base support for effortless drilling or getting oblique holes The aluminum guide rail makes the drill rigs movement more smooth and accurate Wide Application The wet diamond core drilling rig can be widely used in drilling reinforced concrete red brick marble and other materials It is for installing air conditioners pipes stair railings, and repairing highways, etc.