4pc's - dry diamond bit with hexagonal . Dimensions: 1/4 inch (6mm), 5/16 inch (8mm), 3/8 inch (10mm), 1/2 inch (12mm) Application - Diamond bits are designed for use in ceramics, ceramics, granite, , masonry, concrete, various types of tiles and . Performance - Vacuum brazing diamond technology provides fast, chip-free holes while maintaining a long service life. Tool handle - The quick-change hexagonal tool handle provides better chuck grip and is suitable for different types of drill bits. Self-cooling - diamond bit is combined with wax. Wax melts during drilling, absorbs and dissipates heat, thus achieving dry drilling (water can be added to prolong the service life and harder ). Color: black Material: metal Package Contents: 4 x drill 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.