The PS-0505 is a high efficency step down power supply. It plugs directly into the accessory output on most transformers to give a regulated 5volt 500mA output. This is ideal to power LED lighting and other accessories around your layout to bring it to life. Screw terminals for both the inputs and outputs eliminates the need for soldering. The PS-0505 is fuse protected which can be bypassed, and comes with an on board power indicator LED.