This Keep-Alive® includes a Blue and a Black w/ White Stripe wire to attach it to a decoder.
 
Newly-redesigned and coming in at half the size of a KA3, the KA7 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: 18.29mm x 13.46mm x 6.35mm
Scale: HO Scale N Scale
Input Rating: 12 to 16V