MonoRail Surface Transformer-300W El. This single-feed surface transformer converts standard 120 line-voltage to 12 volts to provide the necessary voltage for powering a MonoRail low-voltage lighting system. It can power lamps totaling up to 300 watts. The transformer is concealed inside a decorative housing with a single integral power feed and fast acting secondary short circuit and overload protection that will safely turn the system off should a short occur. Once the short has been removed, the unit can be reset by simply flipping the wall switch off and on.