The UnderLighting kit (underlight) comes with all the parts needed to make an underlight bar. There are five different kits, each with a different color LED. UnderLighting kits can be combined in a daisy chain or connected to a relay for robotic control.
The cost for the UnderLighting kit is $13.00 for the Red, Orange, Yellow, and Green. The Blue kit is $14.50. Shipping and handling is $4.00, but free if the UnderLighting kit is ordered in combination with another robot kit.
Instructions for making UnderLighting