The CMF410 - is the newest model. CMF410 is operated differently from the 400 as it has digital and programmable options.It comes with a wet bowl and stainless steel magnetic pins, which is standard and will efficiently burnish and polish small non-ferrous metals in approximately 20 to 30 minutes. The only recommended medias for your new wet bowl are porcelain, plastic, glass beads and agate beads. The recommended medias for your new dry bowl are corn cob-based, nut-shell based and wood based medias. All other medias will void your warranty. Stainless steel pins are only to be used with original wet bowls.