Ok. So scratch that! The Napa 4040 bulb does not work! It, as well as the other bulbs I've seen at local parts stores have three guide tabs on the back to fit in to housing. My housing only has two tab cut outs in the housing. I did however find one on line that seems to be the same as the Wagner 4420 bulb. It is made by Norman lamps and it is also a 4420 part #. Im gona try that one out to see if it works.