When doing replacement or upgrading on 2009 – 2018 Mercedes-Benz G550 capsule halogen headlamps HID with, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

High Beam and Low Beam Headlight2009 – 2010 9003
Front Fog Light2009 – 2010 H8/H11/H16
Back Up Light2009 – 2010 1156
Brake2009 – 2010 1156
Dome Light2009 – 2010 578
Front Side Marker2009 – 2010 T4W
Front Turn Signal2009 – 2010 1156
License Plate2009 – 2010 12844
Parking Light2009 – 2010 194
Rear Side Marker2010 12929
2009 T4W
Rear Turn Signal2009 – 2010 PY21W
Tail Light2009 – 2010 12821
Luggage Compartment2009 – 2010 6411
Courtesy2009 – 2010 12961
Map Light2009 – 2010 12961
High Beam and Low Beam Headlight2009 – 2010 D1S
Front Fog Light2009 – 2010 H8/H11/H16
Back Up Light2009 – 2010 1156
Brake2009 – 2010 1156
Dome Light2009 – 2010 578
Front Side Marker2009 – 2010 T4W
Front Turn Signal2009 – 2010 1156
License Plate2009 – 2010 12844
Parking Light2009 – 2010 194
Rear Side Marker2009 – 2010 12929
Rear Turn Signal2009 – 2010 PY21W
Tail Light2009 – 2010 12821
Luggage Compartment2009 – 2010 6411
Courtesy2009 – 2010 12961
Map Light2009 – 2010 12961
High Beam and Low Beam Headlight2011 – 2018 D1S
Front Fog Light2011 – 2018 H8/H11/H16
Back Up Light2011 – 2018 1156
Brake2011 – 2013, 2015 – 2018 1157
2014 P21/5W
Dome Light2011 – 2018 578
Front Side Marker2011 – 2018 T4W
Front Turn Signal2011 – 2018 PY21W
License Plate2011 – 2018 12844
Parking Light2011 – 2018 194
Rear Side Marker2011 – 2018 12821
Rear Turn Signal2011 – 2018 PY21W
Tail Light2011 – 2018 1157
Luggage Compartment2011 – 2018 6411
Glove Box2011 – 2018 12818
Interior Door2011 – 2018 194
Map Light2011 – 2018 12961
Stepwell2011 – 2018 12961