This is the 3ft extension rail to be used with the Light Rail 3.5. You can use this rail by itself, or add it onto the 6.5 ft rail that comes with the Light Rail 3.5. Move your lights back & forth across your growing area with a light mover. Increase your coverage area! These motors offer a 0-60 second time delay. Two year warranty on 6 & 10 RPM 3.5 motors.