What you'd use it for
The Double Rainbow is the dual row version of the Quasar Science linear LED tube, carrying two rows of multi-pixel RGBX emitters in one body rather than one row. It gives you a single fixture where you would otherwise rig a pair, which keeps overheads, background washes and hidden practicals quicker to hang and quicker to control. The 2ft draws 50W and the 4ft draws 100W, so pick the length that suits the set and the truck.
Length picks the fixture: 2ft at 50W or 4ft at 100W. Power cable picks the plug supplied in the box.
Figures published by Quasar Science.