Light Rail 3.0, 3.5 & 4.0 Wheel Slave Auxiliary Trolley for Add-A-Lamp Kit Exclusive to LightRail 3.0, 3.5, and 4.0 Can be used to festoon your lamps power cords and cooling ducts [Instruction Manual][1] Click to See "[Frequently Asked Questions][2]" Part Number: TRAUXLR3