and high quality. Made of high quality steel, the blade is extremely sharped, and resistance to cutting. Have good perforation capability. Effective length of 20mm, can process the thick steel plate, and the thick-walled metal pipe material perforation. When cutting Chilled materials, should be filling cooling liquid. Can be clamped on hand drill and benchs drill, can be used for thick steel plates, cast iron, stainless steel, non-standard angle iron and other metal open hole. Diameter: 22 - 65mm( 22mm 30mm 35mm 45mm 50mm 65mm) length: about 68mm Diameter: about 9mm Colour:Photo Color Material:steel Package Contents: 6 x Carbide Tip Drill Bit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.