Wash dividers fit into the central water tank of the Optima12, 16 and 20. Each tank can support up to 11 dividers which make a rack of 12 wash slots. You need to buy the correct size wash dividers for your Optima unit.
If you buy 11 dividers you will receive a complimentary divider comb. This keeps the dividers straight when not in use.
On their own the wash dividers offer a static water bath (though you can fill up the optima by hand to cycle water). For greater efficiency, simplicity and speed you can use the water kit, which is all the pipes and fittings you need to attach the unit to your water supply.