I was wary of paying the listed price for an adapter, which I assumed would be like other ones around the house. In fact, this is a robust and hefty unit which is probably worth the money. It certainly will not fit in a purse or handbag. It is a simple matter to get a deep-cycle battery or two and a perpetual charger and have a system which will run at least all night and maybe longer. Our longest outage so far has been three days, and that is what I planned for, with two batteries. I bought a small NOCO charger from another vendor. AT ALL TIMES AVOID ACCIDENTALLY CROSSING THE BATTERY TERMINALS. This warning should be more prominent in association with this wiring set.