You have a lot of money wrapped up in your Model B single-drum tumbler, now make it more versatile with this kit which converts it to a double 3-pound drum operation. Conversion kit automatically adjusts drum speed for perfect operation. You can then run 3 pound, 6 pound or 15 pound batches. Comes with the two 3-pound drums and both quick-change shafts. Changeover time = 30 seconds!