NATIONAL GEOGRAPHIC Professional Rock Tumbling Kit - Patent-Pending Rock Polisher for Kids & Adults, Platinum Series Ultra Quiet, 2 lb. Barrel, Rocks, Grit, GemFoam Polisher, Rock Tumblers for Adults is up for auction in Toys & Games. The current bid is $20.00, 83% below the $119.99 MSRP, in Good Condition. This auction has ended — similar items appear in live auctions regularly.