Mitsubishi Part Number: W3T13271, W3T 13271. BMW Part Number : 63126948180, 63 12 6 948 180. E90 E91 Pre Facelift 2005-2008. This is forone (single) replica ballast (details below). Xenon Ballast. If you have tried changing the bulb and it is still not illuminating then chances are you have had a ballast fail.
