set2: 30 x glass shelf support + 15 x glass perforated sawsThis diamond coated core drill removes a circle of glass, tiles, marble, granite, ceramics, etc.Can be used with a standard electric drill.Easy to handle. Start the holes diagonally, make a round track and then drill and hold.Note: need lubrication (water), otherwise the diamond core drill will burn. Made of high-quality zinc alloy, the surface is polished, corrosion-resistant and not easy to break, rust-resistant, corrosion-resistant, and can be used for a longer time.Shaft bore diameter: 4 mm, total length: 5 cm).Drill Bit - Glass and Tiles Hollow Core Drill Bit Extractor Remover Tools for glass, ceramic, porcelain, ceramic tileEspecially hard stoneware such as marble, tiles, granite and ceramics can be difficult and clean process. The problem solver for drilling in these materials is the diamond hollow drill.The drills are characterized by a very long service life and fast drilling progress. Diamonds dissolved under vacuum guarantee a precise cut and a long service life.Start your hole schraeg, make a round and then keep drilling straightSaegerand with high-quality industrial diamonds, which drill problem-free and precisely also by hardest materialsWhen using you should note the following:do not use a center drill.When drilling extra hard porcelain stoneware, slightly tilt the drill initially. Slowly raise the drill vertically after drilling.While drilling, gently stir with the drill to better dissipate the dust.let the tool work on its own and exert very little pressure. Keep cool breaks. constantly needs water to cool lubricate.silverMaterial: Emery/stainless steelglass shelf support Size: 18.7xx13.1x5.4mm(0.53 x 077 x 0.59in)Screw size: 13.9mm (0.54in)colour:SilverPackage Contents:30 x glass shelf support30 x screw15 x glass perforated sawsOnly the above package content, other products are not included.Note: Light 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.