... 2.Longer life-span than electroplated tool 3.faster engraveing speed LONGXIANG stone engraving bits include A, B, C, D, E ... gravestone , ceramic tiles, glass, marble, etc. 2. Applicable engraving : Multifunctional, like 3D relief sculpturing ,cutting and thick line-relief U-shaped ... of Chinese Diamond Tools industry. EM12-1210 Diamond Engraving Tool Bit for Carving Stone Marble Granite letter&Relief