The LaisDcc KungFu Stayin Alive Kits are used to supply power to decoders during times of power interruption due to dirty track or problematic track work It will power an HO Scale locomotive for approximately 6 to 20 seconds (depending on the locomotive and the efficiency of the motor). It includes a blue and a black wire with which to attach it to a decoder. The blue wire is the positive/DC+, the black wire is the GND. You can use it with sound decoders and mobile decoders.