Home Depot's Hampton Bay 3 puck undercabinet light set comes with an extension line to wire up to 6 pucks on one transformer. The ends of the line are slightly dissimilar and will mate only with either the input or output socket, not both. Does this indicate a required polarity or what? I want to install plugs at the pucks to (A) facilitate future replacement of pucks without access to the wires and (B) extend the distance between pucks. Thanks for your time and attention,

Steve T.

If the ones I'm thinking of, extend the distance between the lights, and only plug in 1 way.
Maybe to keep multiple sets from accidentally apply power in both directions and possibly a direct connection between the hot and neutral.