Is HB4 same as 9006?
Yes, the HB4 is the same as 9006. via
Is 9003 same as H4?
On the outside, there is absolutely no difference between H4 and 9003. Both share the same housing, the same dual-filament internals, and the same three-pronged connection. So, of course, they are interchangeable, i.e., installing a 9003 bulb in a vehicle equipped with H4s, and vice-versa. via