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 durable, 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 surface, 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, granite, ceramic, marble, and more. Note: not applicable 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.