1. Size: 16mm, 18.5mm, 20mm, 25mm, 30mm 2. Material: high speed steel 3. Function: cooperate with power tools, such as bench drills, to make holes in metal plates such as steel plates, iron plates, aluminum plates, etc. 4. Process: polishing 5. Features: high-quality materials, wear-resistant and not easy to crack, high-temperature quenching, more robust, polished, not easy to rust
