The Keep-Alive™ (KA) devices are used to supply power to decoders during times of power interruption due to dirty track or problematic track work.
KA3 will power an HO-Scale locomotive with headlights on for approximately 6 to 20 seconds (depending on the locomotive and the efficiency of the motor).
This Keep-Alive™ includes a 2-Pin Quick Connector Harness with which to attach it to a decoder.