Description 15 PCS a set diamond drill bits, hole saw core drill style bit. More than 20 years of experience in the production of glass drill bits, combining advanced technology and scientific achievements, performance.Fine workmanship and super wear-resistant, sharp Operation Start the hole diagonally, make a round braid and then hold drill straight.Water is required for lubrication when drilling WARNING Not for use on Concrete or for depths beyond about 1/2" Water is required for lubrication when drilling. Tile Hole Saw15 Sizes 6/ 8/ 10/ 12/ 14/ 16/ 18/ 20/ 22/ 25/ 26/ 28/ 30/ 40/ 50 mm SPEED KILLS This tile hole saw are made of industrial grade carbon steel with nickel-plated coated body that resist corrosion.Reduced drill speeds, low drill pressure and increased use of water lubrication will extend drill bit life considerably 10PCS Hole Saw Set 12PCS Masonry Drill Bits Set Adjustable Threaded Bed Frame Anti-Shake Tool for Bed M42 Bi-Metal Hole Saw 50PCS Mini Funnels 18PCS Drill Bits Material Metal Metal Metal Metal Plastic Metal quantity 10pcs 12pcs 3pcs 2pcs 50PCS 10PCS Can return or exchange