depends on your car/suv/truck/rig socket

some large rigs come with 7 way socket, you just need to buy a 7 way power cord and connect to toad.  for most cars or light trucks (1t or below), the output of signal lights is 4 way flat connectors. obviously you will use the flat 4 way cord for those.

(i am using a 7 way.  the nicest thing is i can connect the live 12v power to the toad battery, so my toad battery is always full).