Rotary tumblers polish rocks, stones, coins, clean cartridges, polish brass and other metals Excellent for studio and small jewelry projects Used with stainless steel shots or media to be purchased separately Process times are longer than vibratory finishing, but a distinct advantage is that the surface of work pieces get work hardened Barrel is multi sided, made of tough polycarbonate, are leak proof and will not corrode or rust, use with all types of media including steel shot.