Have you ever looked up a bulb number for that HID or LED headlight conversion install you were doing and the bulb size didn’t match any part numbers? Here is a list of the most common bulb bases that you’ll need to cross reference.
9003 is the same as H4
HB2 is the same as H4
HB1 is the same as 9004
HB3 is the same as 9005
HB4 is the same as 9006
HB5 is the same as 9007
9008 is the same as H13
9145, 9140 is the same as H10
800, 891, 889 series bulbs are the same as 880
9012 is the same as 9006
H16 is the same as 5202
H8 and H9 is the same as H11