Specifications: Motor: 120V/60Hz Barrel Capacity: 23LB Material: sheet metal ,rubber Easy-to-follow rock tumbling instructions Noise reducing leak-proof barrel with aluminum lid High-quality tumbling machine with powerful motor that will last for years Explanation: The motion in the barrel of the Tumbler simulates the natural action of flowing water or ocean waves. Beaches and riverbeds contain rocks and pebbles smoothed by water and the abrasive sand it carries. As rocks grind upon one another with constant water and sand in the mix, they begin to round and smooth. Although this is a constant process, it does not however, naturally polish the rocks The Tumbler uses an abrasive media instead of sand. It is graded by grain size, from fine powder sized grains, up to large sized grains. By changing (usually by weekly intervals) the grain size, rotating from coarse, medium, to fine, the rock or gemstone is smoothed much more quickly than the natural process To polish using a Tumbler, add a metallic oxide compound (not included). The complete process for a gemstone or rock to go from rough to smooth, polished finish, usually takes 4-6 weeks Great way to start a rock collection: Rock tumbling is a fun activity for children of all ages and promotes an interest in geology and science. Introduce your kid to science the fun way. Satisfaction Guaranteed - With a manufacturer warranty you can be sure you will get a quality gift.CAUTION: Not recommended for Children under 12 ages