This is a H4 P43t base (12V 60/55W) blue halogen bulb. It is interchangeable with LLB472 bulbs (part number 9003).
It is correct for our Lucas H4 and PF700 headlamps, among others; see Related Products below.
We also carry genuine Lucas LLB472 white halogen bulbs and high output LLB472X xenon bulbs (30% brighter) for the same applications, as well as several other headlamp bulbs; some can be seen in Related Products below.