Tresco Lighting L-LED-LINKD-180-1 12V DC Linking/Extension Cord, 72" 6" (15Cm) length Used to extend distance from 12V dc power supply output to run of lights/mounting block for any tresco lights Used to extend reach of the starter cord that plugs into any tresco light(s) Used for linking/"daisy-chaining" tresco lighting elli v or elli 2 led fixtures Used for connecting tresco lighting elli v or elli 2 led fixtures to power supply/mounting block