Question: what is the difference between h1 and h3 bulbs?
Answer: The H1 appears to be longer and thinner, and the bulbs both have different bases. The H1 bulb uses a P14. 5 base, whilst the H3 bulb uses a PK22s base and has a wire protruding from the bottom. ... Your dipped beam and high beam will need one specific fitting of bulb and only one bulb can fit.