14 Piece Diamond Hole Saw Kit. DTA® electroplated diamond drill bits are specially designed to last longer. They are intended to be used with porcelain, ceramic and natural stone and work with standard variable speed drills. Electroplated diamond drill bits need to be used with water. Set includes in a aluminum carrying case the cutter sizes; 5/32″, 1/4″, 5/16″ 3/8″, 1/2″, 5/8″, 7/8″, 1″, 1-1/4″, 1-3/8″, 1-9/16″ with a 4″ steel universal drill guide and 37.2 oz (1.1L) cooling system. Designed to be used with water. DTA has been serving the tile industry and contractors for over 40 years. Quality is our reputation.