H4 LED bulbs
H4 LED bulbs are bulbs based on the halogen H4 design. This means the base etc. are based on the H4 fitment, but the light source is LED instead of halogen. It also has the low and high beam function as a regular H4 halogen bulb. A big advantage is the increase of light output, a disadvantage is usually more stray light, which can be blinding for oncoming traffic.
Also the light temperature or color is higher, which means a more white light. There are LED bulbs with a lower K rating to have a higher light output, but a classic look, like the Osram HL vintage product line.
Installation
Installation is usually quite easy because the base of H4 LED bulbs is based on H4 halogen bulbs. To prevent canbus messages / errors sometimes it is needed to have canbus cancellers. And in few occasions caps are needed because LED bulbs usually require more room at the rear because they are bigger because of the cooling fans.
Use on public roads
Because the H4 standard is originally designed for halogen, most H4 LED bulbs are not approved for the public road. But fortunately there are ECE approved options from Osram and Philips. Please be aware they are not approved for all vehicles, please always check the most up-to-date information from Osram or Philips
