Magnetic tumblers are very efficient. For tumbling bangle bracelets,
you will need at least a 6" bowl and preferably a 9" bowl diameter
to do a good job. If you are working on linked bracelets, the
smaller 6" diameter bowl will do a good job. The smaller 6" units
are fine on a up to possibly 30 rings at a time. When you over load
these units their efficiency goes down and so does the quality of
your results. The larger the unit, the more items you can tumble at
Phillip Scott G.G.