H11 Bulb vs. H4 Bulb
Comparing 2 standards across 11 specifications. 11 key differences identified.
The H11 Bulb (standardized under UN ECE Regulation 37 with a PGJ19-2 right-angle plastic base) is the modern standard for front fog lights and projector low-beam headlights. Featuring a built-in silicone weather-sealing O-ring, an integrated 90-degree automotive locking connector, and an axial 55W filament generating 1,350 lumens.
The H4 Bulb (marketed as 9003 or HB2 in North America under DOT regulations, standardized with a P43t 3-prong base) is the legendary dual-filament automotive headlight bulb. Containing both a 55W low-beam filament (equipped with an internal stamped metal anti-glare shield cup) and a 60W high-beam filament inside a single halogen quartz glass capsule.
Specification Comparison Table
11 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standardization
|
UN ECE R37 Category H11 / US DOT Category H11 | UN ECE R37 (H4) / US DOT FMVSS 108 (HB2 / 9003) / IEC 60061-1 |
|
Base Socket Designation
|
PGJ19-2 (Right-angle molded plastic base with 3 asymmetrical metal locking tabs) | P43t (3 large radial metal locating tabs with 3 heavy electrical blade terminals) |
|
Luminous Flux Output
|
1,350 lumens ± 10% (at 13.2 V) | Low Beam: 1,000 lumens ± 15% | High Beam: 1,650 lumens ± 15% (at 13.2 V) |
|
Weatherproofing
|
Integrated orange high-temperature silicone O-ring seals directly against headlight housing barrel | — |
|
Nominal Power & Voltage
|
55 W @ 12V (tested at 13.2 V; draws 4.17 A) | — |
|
Electrical Plug
|
Integrated female automotive connector with locking snap tab (IEC 60061-1) | — |
|
Related Family (H8 / H9 / H16)
|
H8: 35W (PGJ19-1) | H9: 65W (PGJ19-5, 2100 lm) | H11: 55W (PGJ19-2) | H16: 19W (PGJ19-3) | — |
|
Filament Architecture
|
— | Dual tungsten filaments: Low Beam (55W) + High Beam (60W) |
|
Internal Anti-Glare Shield
|
— | Stamped nickel cup positioned under the low-beam filament blocks downward light, creating a crisp horizontal beam cutoff |
|
Electrical Connector
|
— | 3-prong female socket (Ground, Low Beam 12V+, High Beam 12V+) |
|
Application Domain
|
— | Standard in motorcycles (single headlight unit), compact hatchbacks, classic 7-inch round sealed-beam replacements |