Full Kit: It contains 1pcs quick change drill bit holder, 12 pieces of diamond core drill bits (2 pcs 5mm, 2 pcs 6mm, 2 pcs 8mm, 2 pcs 10mm, 2 pcs 12mm, 14mm and 16mm). Multiple sizes and enough quantity provide wide drilling needs and replacements. Convenient and Efficiency: The tile drill bits are crafted by vacuum-brazed diamond technology, and coated in diamond particles, It is stable and , provide faster and more precise drilling. The bit holder can be used as an extension rod to use in narrow places. Dry Drilling Design: Diamond drill bits integrated with wax inside melt while dry drilling cools the cutting , preventing overheating to provide smooth drilling and long-lasting life. Note: 5-12mm diamond drill bit filled with cooling wax inside and 14mm andamp;16mm drill bit without wax. Universal and Portable: Both of the tile drill bits and bit holders are 1/4-inch hex shanks. The shank can easily be installed with most rotary tools. Quick installation and replacement, diamond drill bits set for porcelain tile come with a box so that it is easy to carry and store. Wide Application: The diamond hole saw drill bits are made of premium Aluminum alloy, which can be used on tiles, porcelain, stone, glass, , ceramic, marble, and more. Note: for wood. Colour:As Shown Material:Aluminum alloy Package Contents: 1set * hole saw drill bit 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.