The multi color change set i got from Amazon LINK
(same as pictured on page 1 of this thread) are 16' long LED strand. You can pick any of several colors at the push of a button. Very nice set that has everything you need in one box. If you need to splice 2 strands together you can easily do with butt splices or solder and heat shrink. i will see if i can post a pick of the ends.
The white end attaches to the transformer and sensor. The 4 wires can be spliced to another set.