brand new and high quality. Features: --Ideal for drilling ceramic tiles, glass, marble, slate and porcelain tiles. --Diamond hole saw tile ceramic glass porcelain marble drill. --Need Cooling and lubrication,for always use lubrication (water) , otherwise the diamond core will over heat. Use method: 1.Clamped firmly to a for bench to allow for slow controlled drilling. 2.Make a template from a piece of timber or waste material, locate this over the area where you want to drill your hole and use it as a "guide" to start the hole. 3.Once you've got into the surface by 1mm to 2mm you can remove the guide and continue to drill in a controlled manner. 4.Start your hole diagonally, make a round trace and then hold drill straight. Specifications: Color: silver Material: steel Size: 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 26mm Quantity: 5pcs Note: Transition: 1cm=10mm=0.39inch Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 5 Diamond Hole Saw