Get the grit you need for polishing. This kit includes the following media: (2) 4-oz. coarse, (2) 4-oz. fine, (2) 2-oz. pre-polish, (2) 2-oz. polish. There is enough supplies to complete the polishing process in two barrels.
Good quality grit and a good amount in each bag to do 2 small loads of stones. Sapphires given up as non gem quality because of scratches, polished up 5 more stones for the gem cutter!
I used this rock polishing grit in the AR-12 tumbler. The amount sent was appropriate for the size of the AR-12 tumbler. It worked as advertized. The instructions imply to put a new batch in with each load, but I found it works OK for several succesive loads (it does eventually wear out). My son and I have tumbled several interesting rock batches and I am happy with the results.