Convert any hot tub to a salt water hot tub with this device. Plug into any GFCI protected outlet, mount the controller, and hang the electrolytic cell over the edge of the hot tub in the water. Add some pure salt and you are set. This unit has a built in sensor to prevent over chlorination, which is very usefull and better than devices that are based on timers only. We recommend using a sacraficial anode with all salt systems, call us for more info about this very good product.