Read about IPF's illumination upgrade with a plug-in headlamp harness, H4 halogen bulbs and H4 halogen headlight inserts, only on 4wdandsportutility.com, the official website of 4 Wheel Drive ...

Custom Headlights With IPF H4 Bulbs - Bolt-In Brilliance. High-performance headlamps for your truck. Ken Brubaker Writer Jul 01, 2002. See All 11 Photos. See All 11 Photos.

Our test concentrated on H4 or 472 bulbs. These have been around since the Sixties and have two filaments, one for dip and the other for main beam. They are used in cars with single headlamps.