the company was established in 1988; our current products are carbon steel hole saw,bi-metal hole saw and forstner bit; we are able to make the best combination of customer¡¯s requirement,product¡¯s quality and price; we try our best to develop the market. 1. it is made from heat-treated high carbon steel. hardness:hrc50-55 2. diameter:1/4¡±--2-1/8¡±. 3. cutting depth:75mm 4. used for cutting wood plaster splint, and plastic.