Underground Lighting H1 collection is built exclusively around the H1 headlight bulb, an OEM single-beam bulb standard defined by its P14.5S metal flange base and single spade electrical terminal. The H1 bulb operates on a 12V passenger-vehicle electrical system, uses a spring-clip retention method, and requires very precise alignment because beam shape and cutoff are controlled entirely by the headlight housing, not the bulb itself.
Physically, the H1 format is optimised for tight headlight housings, with a ~8.5 mm glass capsule diameter, ~55 mm overall length, and ~14.5 mm base diameter. This compact geometry is why H1 bulbs are commonly used in projector headlights, reflector housings, and select fog or auxiliary lighting applications where space and focal accuracy are critical.
The collection includes H1 technology variants, covering OEM replacement, H1 LED retrofit, and HID conversion use cases:
H1 HID Replacement Bulbs – 3700 Lumens (PAIR)
Xenon HID arc bulbs are designed for existing H1 HID systems, producing light via an electric arc inside a xenon-gas quartz capsule. When operated with a 35W ballast, output reaches ~3700 lumens per pair. Available in 3000K yellow, 6000K white, 8000K white/blue, and 10000K blue.
H1 PNP HID 35W CANbus Error & Flicker-Free Kit (PAIR)
A complete halogen-to-HID conversion kit including H1 xenon bulbs, electronic ballasts, igniters, and CANbus circuitry. Ignition voltage peaks at ~23,000V, followed by a ~85V AC sustained phase. CANbus load simulation prevents flicker, bulb-out warnings, and ECU errors.
H1 LED Headlight Bulbs – 40W 6000LM (PAIR)
High-output solid-state LED H1 replacements using electroluminescence at a p-n junction. These bulbs deliver up to 6000 lumens per pair at 40W, producing 6000K daylight-white light. Designed for projector and reflector housings with correct focal alignment.
H1 LED CSP Bulbs – 2000LM (PAIR)
Compact LED H1 bulbs using CSP (Chip-Scale Package) LEDs, producing ~2000 lumens per pair at 6000K white. Optimised for tight housings, fog-light use, and applications requiring controlled brightness and thermal stability.
Across all four products, the H1 platform remains a single-beam solution, suitable for low beam, high beam, or auxiliary roles, depending on vehicle design. Because the H1 bulb itself has no integrated cutoff or indexing, housing optics and installation accuracy are the primary determinants of road performance and glare control.
Don’t forget to explore our range of fog lights, turn signals, auxiliary lights and switchback turn signal lights—check vehicle compatibility using our bulb finder
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