Hella H4 5.75 in Round Halogen Headlamp Reflector 12V

This is the Hella H4 halogen headlamp reflector, a 5.75-inch round replacement optic that drops into the classic 5 3/4-inch round headlight bucket you'll find on decades of cars, motorcycles, trucks, and off-road rigs. It's the reflector-and-lens unit itself, built to take a standard H4 bulb, sold as a single piece so you can replace one side, both sides, or a cracked lens without buying a whole new light assembly.

One thing to be clear about up front: it ships without a bulb. That's on purpose. The H4 is one of the most common headlight bulbs on the planet, so Hella lets you pick the exact bulb you want and drop it in. If you've shopped bulbs before, you already know the H4 by its other names. It's the same thing as a 9003 and an HB2, all sharing the P43t base, and it runs on 12 volts in this application. Grab a standard 60/55-watt H4 and you're set. No adapter, no splicing, it just seats into the reflector.

Here's why the H4 is such a nice bulb to build around. It's a dual-filament design, which means one bulb gives you both your high beam and your low beam. Flip to low and one filament lights with a shield cutting glare for oncoming traffic. Pull high and the second filament fires for full reach down the road. That's the whole beauty of a 5.75-inch H4 setup: simple wiring, one bulb per lamp, and a beam pattern that's been proven on the road for a long, long time.

This unit is ECE approved. ECE is the European and international road-lighting standard, so the optic is cut to throw a proper ECE beam pattern. If you're building a European-market car, a classic, a cafe racer, or anything headed for a country that runs ECE rules, that approval matters. If you're in the States, check your local rules before you rely on it for street use, since the US runs its own DOT standard. Either way, for show cars, track builds, off-road trucks, side-by-sides, tractors, and utility equipment, an ECE H4 optic is a clean, bright, honest replacement.

It's sold as a single lamp. Most vehicles run a pair up front, so if you're refreshing both sides, order two and you'll have a matched set with the same optic and the same beam. Replacing just one cracked or hazed lens? A single is exactly what you want, and it'll match the other side since it's the same part.

Fitment is the standard 5 3/4-inch round pattern, so it seats into the same bucket and retaining ring your old sealed beam or reflector used. Wire it to a 12-volt supply, seat your H4 bulb, and aim it. A quick tip from experience: park about 25 feet off a flat wall on level ground, mark your headlight center height, and adjust so the top of the low-beam cutoff sits just below that mark. Ten minutes with a screwdriver and you've got a beam that lights the road instead of blinding the guy coming the other way.

Why Hella? Because a headlamp reflector lives a hard life. Heat cycles, road grime, vibration, weather. Hella has been making automotive and utility lighting for a very long time, and the reason people keep reaching for their optics is consistency: a clean reflector surface, a lens that holds its clarity, and a beam that actually goes where the standard says it should. Pair this reflector with a fresh H4 bulb and you get a noticeable step up over a tired, yellowed old lamp.

So who's this for? Anyone running a 5.75-inch round headlight who wants a proper ECE halogen optic and the freedom to choose their own H4 bulb. Classic car owners, motorcycle builders, off-road and utility folks, and anyone doing a headlight refresh on a budget. Just remember to add an H4 bulb to your cart, since this one comes ready for it but doesn't include it.