Automatic Transfer Switches connect your 120V appliances to generator power when generator is activated. No need to go outside, remove the shoreline plug from the outlet and plug it into the generator receptacle. Automatically connects your appliances to shoreline power when you plug into the park outlet. No maintenance required. Mounts in any position in RV's living area or basement storage compartment. Not designed for exterior use or installation in a battery compartment or other compartment with flammable materials. UL listed.