Discover with Dr. Cool Rock Tumbler Set - Turn Rocks Into Stunning Gemstones POLISH ROCKS AT HOME  Discover the fun hobby of rock tumbling and transform rough rocks into beautiful gems COMPLETE ROCK TUMBLING KIT  Includes tumbling stones (9 types), polishing grit (4 types), jewelry fastenings, and instructions QUALITY TUMBLING MACHINE  Featuring a high-powered motor, this is a workhorse machine that will last for years START A ROCK COLLECTION  Spark a childs love of geology and learning with this hands-on earth science kit 100% SATISFACTION GUARANTEE - Join the millions of parents who have chosen our award-winning science toys and experience the Discover with Dr. Cool difference!