Open box unit. Completely unused. Still has plastic protective film on metal base of unit. Includes all accessories, manual, and original box.

Per the manufacturer: 
The Dometic SmartStart accessory for RVs is a soft starter that reduces AC start-up power demand by as much as 75%. This innovative device enables air conditioners to run on a generator as small as 2,000W, helping to eliminate the need for shore power and making boondocking easy. Specifically developed for RV air conditioners, it also makes it possible to use an inverter in a solar application without faulting. With the SmartStart AC Accessory, RV owners have the option of moving to a smaller generator, saving weight and money while enjoying quieter AC startups at any time of day or night.