37-155 Diamond Twist Drill Bit Set High Speed (Or Hand Twist with Zona Twist Drill). 20-piece high speed twist drill bits #61 - #80. Straight shank, high quality steel, diamond coated in 5-in. x 2-3/8-in. plastic case. Drill stone, ceramics, tile, glass, and hard metals. Use for jewelery, bead making and other crafts. Fits Zona and other hand drills or rotary tools such as Foredom, Dremel, etc. with micro chuck. These High Speed Twist Drills is especially designed for Zona Hand Drills, Bit Holders, and Bit Vise Adapters.