Made of YG8C alloy, welded by manual high frequency. After high temperature quenching, the hardness is greatly improved, and the treatment of the series makes this product more beautiful than ordinary low carbon steel drills from appearance to use, and has a longer service life. Suitable for concrete, cement, stone, etc. Material:YG8C alloy colour:Gray Package Contents: 11 x drill 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.