The H7 bulb was introduced as an improvement on the H4 bulb. The “H” refers to halogen. These bulbs contain a tungsten filament enclosed in a halogen gas-filled quartz capsule. This allows higher ...

We tested the low-beam performance of single-filament (9003) and dual-filament (H7) bulbs from GE ... deliver a whiter light and up to 19 percent more output than the standard or OE bulbs ...