Known part numbers:

3D0-907-391-A / 3D0-907-391-B

3D0907391A     / 3D0907391B

3D0 907 391 A  / 3D0 907 391 B

8E0 907 391 A  / 8E0 907 391 B

8E0-907-391-A / 8E0-907-391-B 

8E0907391A     / 8E0907391B

Believed to fit:

2002- Alfa Romeo
 

Renault

2002- Megane
2001- Laguna
2002- Clio 
 

Seat

2003- Ibiza
2003- Cordoba
 

2004- Porsche Cayenne
 

VW

2006- Passat
2004- Touareg Bi-xenon
 

Citroen

2004- C4

2004- C5
 

Peugeot  607, 807, 407

03-05 Audi A4 S4
03-05 Volvo S80 
03-06 Volvo S60

01-06 Volvo V70
03-06 Volvo XC90 
04-06 Jaguar XJ8 XJR
05-06 Chrysler 300C SRT 8
03-07 Cadillac SRX

03-07 Cadillac CTS use 2 type ballasts. one with 4 pin power cord and other one use 12 pin, make sure this is the same ballast as the one in your car. you can check it from the rear low beam.