Size: Total 6 pieces, 5 pcs dry diamond drill bits (1/4" 6mm+5/16" 8mm+3/8" 10mm+1/2" 12mm+9/16" 14mm) and 1pc Carbide Drill (1/4" 6mm), Hex Shank Quick-fit. Application: Dry drilling for Granite, Tile, Ceramic, Marble, Stone, Porcelain, Masonry. Use water for longer time. Wax inside: For cooling,our Diamond Tipped Drill Bits have wax cores built-in which automatically absorb and dissipate heat as you go. Vacuum Brazed technology: Higher efficiency, faster working speed, longer service life. Diamond material upgraded, can drill 10-15 more holes than ordinary drill bits. Note: The cross hole opener is to provide accurate positioning for diamond bit, not recommended for drilling；Hand drill at 2000-5000RPM, the slower the shorter the life.