1. The blade is made of Hard alloy, which is very and resistant to cutting. It has good perforating ability. 2. It can process thick steel plates and thick-walled metal pipes. 3 When cutting the cooling material, the should be filled with coolant. 4. It can be clamped on hand drills and bench drills, and can be used for metal eyes such as thick steel plates, cast iron, stainless steel, non-standard angle iron, etc. Type: Coring bit Colour:Silver Material:Hard alloy Size:16mm 18mm 20mm 22mm 25mm 26mm 28mm 30mm 35mm 40mm 45mm 50mm 53mm Package Contents: 13 x Core Drill Bit Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.