Well, depends what you have. If it is the standard H4, you just need the one bulb. (ever change one before?) I like the Sylvania Silver Star, it's white instead of the yellow of the standard bulb. If you have a Wallmart handy, you can buy them in packs of 2 cheaper then singles in a auto store and you would have to buy a pair if your going to step up to these. They are worth the money. Now, thats not to say they are the only ones out there, but they are readily available and if you do any night driving, you will thank yourself for spending the money. Just remember to wipe them down and don't touch them with your fingers. The oil from them will cause hot spots and burn them out quicker