Features: Scope of use: air conditioning drilling, wall drilling coring, range hood drilling, engineering bridge drilling, construction drilling coring, machine room pipe, etc Standard hex joint, high quality screw hole interface, convenient for loading and unloading drill bits High strength seamless steel tube substrate with high hardness, not easy to deformation,and wear-resistant Sharp edge, thick diamond, wear - resistant, sharp, and not easy to defect Fast drilling , sharp and tough, labor - saving safety, high stability Specification: Material: Diamond Name:Wet Diamond Core Drill Bit Type:51*370, 56*370, 63*370, 71*370(Optional) Package list: 1 x Wet Diamond Core Drill Bit Note: Water drill: water must be added in the process of use, and it should be used for core-cutting project. It is suggested to be matched with fixed or hand-held drill Drill bit installation: firstly, check whether the spindle is swinging and whether the electrical and mechanical parts are normal. Drill bit is loaded to ensure that the drill bit is clamped with the drill and remains concentric.Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.