[HIGH WEAR-RESISTANCE ]These die grinder bits are made of tungsten carbide steel which has long working life with high wear-resistance. [ AND STURDY]for bits are exceptionally , tough, well-balanced, and have an extra , making them ideal for working in small spots rather than grinding discs. [WIDELY USE]The carbide burr set is ideal for fine detail work and may be used on wood, metal, plastic, ceramic, stone, glass, and other materials. [WARM REMINDER]If you try to drill holes in a glass bottle,it is recommended to pour water constantly over the drill site to prevent cracking or chipping. Suitable for mold manufacturing,mechanical chamfering and deburring,welding and metal non-metal processing engraving,etc. Colour:As Shown Material:Tungsten steel Package Contents: 10 x grinder bits Only the above package content, other products are not included. Note: Light reflection 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.