This low voltage 300W 12-15V Landscape Transformer with Timer and Photocell is designed for use with DALS landscape lighting fixtures. It converts input voltage 120V to an output voltage of 12, 13, 14, or 15V, and output power is 300W. This is a constant voltage mode power supply, protected against short circuits and over voltage. It has a fully isolated metal case and cooling by air convection. The timer and photocell sensor can be used to manage when the lights turn on and off. Not dimmable.