Description: Diamond core drill bit, hole puncher fits for air-conditioner and range hood, diameter 20/30/40/51/63/76/102/120mm.     Specification: Color:wine red;  Material:metal alloy;  Size: 1 20x450mm ;  2 30x450mm;  3 40x450mm;  4 51x450mm;  5 63x450mm;  6 76x450mm;  7 102x370mm;  8 120x370mm;     Features:  Great wall shape teeth are sharp and tough.  M22 Thread fit for most of water drill.  360°seamless steel pipe, more durable.  Multifunctional for air condition installation, water pipe, traffics and engine room.     Note:  1. The tool needs to be cleaned before use to ensure accuracy.  2.The cutting amount, rotation speed and cutting fluid should be selected reasonably.  3.After the tool is used, and cleaned and oiled, keep it in a safe place.  4.Check the integrity of the hole drill before use.  5.When drilling the hole, keep the hole perpendicular to the workpiece.  6.Start drilling is to use a small amount of force, and use medium force after positioning.  7.When drilling, the rotation speed should not be too low, so as to avoid the knife jam and cause the knife to collapse.  8.After the drilling and drilling work, the hole drill should be rotated to exit the work.  9.When drilling continuously, the cutting edge should be cooled with cutting fluid.     Package Included: 1x drill