With Blue and a Black w/ White Stripe wire to attach it to a decoder.
 
TCS Keep-Alive® (KA) devices are used to supply power to decoders during times of power interruption due to dirty track or problematic track work.
 
Newly-redesigned and coming in at half the size of a KA3, the KA1 will power HO or N scale locomotives with approximately one-third of the capacitance of KA3/KA4 devices (depending on the locomotive and motor).
 
Dimensions: 27mm x 8.9mm x 6.2mm
Scale: HO Scale N Scale
Input Rating: 12 to 16V