Lortone Tumbler Model 33B has two 3-pound rubber barrels (outer barrel dimensions are 4-1/2" diameter by 4-3/4" high), each with a quick-seal closure. Quiet, sturdy, and simple to operate, this model is perfect for the tumbler with lots of rock to process! Each barrel can be in a different step of the tumbling process, contain rocks of different hardnesses, or contain rocks collected by individual persons. An instruction booklet is included.