WFCO/ Arterra T-30 RV Trailer Camper Electrical Transfer Switch 30A Power Transfer Switch; 30 Series; Transfers Power Between Shore And Generator; Used With Arterra WF-8900 Series Power Inverters; Automatic; 120 Volt AC; 30 Amp; 5 Inch Width x 5-5/8 Inch Height x 5 Inch Depth Designed To Provide Trouble-Free Changeover Of Power Between Shore Power And Generator Engineered For Safe, Reliable Performance, And The Units DC Coil Prevents AC Chatter Noise And Drop-Out In Low-Voltage Conditions Accidental Coupling Of Power From Or To Shore Line And Generator Is Prevented By A "Break Before Make" Configuration