TSP300 300 Watt Low Voltage Transformer with Digital Timer and PhotocellTSP300 User Manual 300W AC 12V Low Voltage Digital Transformer is a reliable choice for indoor and outdoor use and is built with a toroidal coil to ensure efficiency and reduce resistive and winding losses. This high quality digital transformer is made of heavy duty commercial grade plastic and uses national standard 120 volt input which converts to 12 volt output for the safe low voltage that can handle 225 watts load. Its size is 6. 1" (L) x 3. 5"