Broan CWT45 Thermostat for 28-Watt Solar Powered Attic Ventilator Accommodates Broan 28-Watt Solar Powered Attic Ventilators Connects easily Fits model numbers 345CSOBK, 345GOBK, 345GOWW, 345RSOBK, 345RSOWW, 345SOBK and 345SOWW Used where cold weather ventilator operation isn't needed