The teacher's choice when finishing rocks. This vibrating tumbler is useful for smoothing and polishing a wide variety of rocks. Following the provided Tumble-Vibe four-step finishing process, students are guaranteed success in getting good finishing results. Up to four pounds of rocks can be processed at one time. A second bowl is recommended for quality polishing, as residual grit from the grinding and smoothing process will become imbedded in the first bowl, preventing a good final polish. Grain, polishes, and a rock finishing kit are sold separately.