Product Description from the Manufacturer

The most unique automatic transfer switch ever! When utility power goes out, GenTran's PowerStay Automatic system starts your generator and transfers circuits to generator power in sequence according to priority assigned at installation - so there's no need to oversize your generator for the initial transfer! This "smart switch" actively manages each circuit on generator power and shuts off lower priority circuits as demand increases on higher priority circuits. Run all the essentials with this Model 3000. Like the furnace, refrigerator/freezer, microwave, well/sump pump, lights, television, garage door opener, water heater, security system, dishwasher, clothes dryer. Since no subpanel is required, installation takes less time than traditional automatic transfer switches. Can be flush mounted or surface mounted indoors. Comes prewired and includes wiring harness. Built-in battery charger keeps generator battery charged, but won't boil the battery acid. Automatically exercises generator at regular intervals so make sure it's ready when you need it. Ideal for homes susceptible to frequent power outages, work-at-home professionals, households caring for elderly or sick relatives, as well as second homes. Works with any permanently installed natural gas, propane, diesel or gasoline-powered generators equipped with remote electric start. Automatic choke required for gasoline engines. UL Listed. Made in USA. 24 month warranty. Customer support available at 1-888-GEN-TRAN.

Source from Amazon