Choose the barrel size that"s right for the job with the Diamond Pacific MT-14 Mini-Sonic Vibrating Rock Tumbler - 2 Hoppers. This tumbler comes with a durable ABS plastic base as well as two hoppers, each made from cast polyvinyl. One hopper holds up to 4 pounds of material and the other holds 10 pounds, so you can use the one that"s best suited to the job. This tumbler operates via electronic vibration. An interrupted electrical current moves the contents of the hopper only, creating a gentle compacting/ separating motion that draws slurry into your materials for effective, uniform polishing that retains the original shape of the pieces. No pulleys, belts, or motors means it lasts longer and is quieter and easier to use. Just control the settings via the built-in electronic dials on the base. The Mini-Sonic operates with 3600 vibrations per minute on 60Hz of power. Only a small amount of water and abrasive is required for operation. Too much of either will cause material to collect in the hopper and prevent proper rotation. About Diamond Pacific For over 30 years this second-generation family-owned business has manufactured equipment for lapidists - from rock hound hobbyists to professional gem cutters and jewelers. Diamond Pacific hopes to put fun and pride into the craft by manufacturing the necessary tools to ensure superior results. * One 10-lb., one 4-lb. capacity hoppers * Cast polyvinyl hoppers * Durable ABS plastic housing * 60Hz; 3600 vibrations per minute * Alternating separation/compacting action * Rotation and vibration powered by electric current