When doing replacement or upgrading on 2007 – 2009 Mercedes-Benz R320 with capsule halogen headlamps HID, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight2007 – 2009 H7
High Beam Headlight2007 – 2009 H7
Back Up Light2007 – 2009 1156
Brake2007 – 2009 1156
Daytime Running Light2007 – 2009 PSX26W
Dome Light2007 – 2009 194
Front Side Marker2007 – 2009 12396NA
Front Turn Signal2007 – 2009 3457NA
License Plate2007 – 2009 12844
Parking Light2007 – 2009 12961
Rear Turn Signal2007 – 2009 PY21W
Tail Light2007 – 2009 1156
Luggage Compartment2007 – 2009 12961
Courtesy2007 – 2009 6418
Map Light2007 – 2009 12961
Low Beam Headlight2007 – 2009 D2S
High Beam Headlight2007 – 2009 H7
Back Up Light2007 – 2009 1156
Brake2007 – 2009 1156
Daytime Running Light2007 – 2009 PSX26W
Dome Light2007 – 2009 194
Front Side Marker2007 – 2009 12396NA
Front Turn Signal2007 – 2009 3457NA
License Plate2007 – 2009 12844
Parking Light2007 – 2009 12961
Rear Turn Signal2007 – 2009 PY21W
Tail Light2007 – 2009 1156
Luggage Compartment2007 – 2009 12961
Courtesy2007 – 2009 6418
Map Light2007 – 2009 12961