Wolo (8104XL-1CCCC) Lightning XL 80 Watt Power Supply Four Bulb Emergency Warning Strobe Kit - 4 Clear Bulbs 4 Clear bulbs Designed for extended length vehicles, providing reliability and high performance The bulbs easily install into a 1 inch hole, which is drilled into each headlight and taillight assembly The power supply, 8004-PS is heavy-duty, with an operating voltage of 12-24 VDC and has four outlets producing 80-watts of output power Engineered with a state-of-the-art field proven microprocessor, to provide years of dependable service