When doing replacement or upgrading on 2006 – 2017 BMW 550i GT xDrive Adaptive 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.

Low Beam Headlight 2006 – 2010 H7
High Beam Headlight 2006 – 2010 H7
Front Fog Light 2006 – 2007 9006
2008 – 2010 H8
Back Up Light 2006 – 2010 921
Brake 2006 – 2010 1156
Dome Light 2008 – 2010 194
Front Turn Signal 2008 – 2010 3457NA
License Plate 2008 – 2010 12844
2006 – 2007 6418
Parking Light 2006 – 2007 12961
2008 – 2010 3357NA
Rear Turn Signal 2006 – 2007 PY21W
Tail Light 2006 – 2007 1156
Front Inner Turn Signal 2006 – 2007 PY21W
Front Outer Turn Signal 2006 – 2007 12396NA
Glove Box 2006 – 2010 DE3423
Interior Door 2006 – 2007 194
Map Light 2008 – 2010 12961
Rear Reading Light 2008 – 2010 194
Stepwell 2006 – 2010 12844
Trunk 2006 – 2010 6411
Low Beam Headlight 2006 – 2007 D1S
High Beam Headlight 2006 – 2007 H7
High Beam and Low Beam Headlight 2008 – 2010, 2014 – 2016 D1S
Front Fog Light 2006 – 2007 9006
2008 – 2010 H8
Back Up Light 2006 – 2010, 2014 – 2016 921
Brake 2006 – 2010 1156
Daytime Running Light 2008 – 2010 H8
Dome Light 2008 – 2010, 2014 – 2016 194
Front Turn Signal 2008 – 2010 3457NA
2014 – 2016 PY24NA
License Plate 2008 – 2010 12844
2006 – 2007 6418
Parking Light 2008 – 2010 3357NA
Rear Turn Signal 2006 – 2007 PY21W
Tail Light 2006 – 2007 1156
Front Inner Turn Signal 2006 – 2007 PY21W
Front Outer Turn Signal 2006 – 2007 12396NA
Glove Box 2006 – 2010 DE3423
Interior Door 2006 – 2007, 2014 – 2016 194
Map Light 2008 – 2010, 2014 – 2016 12961
Rear Reading Light 2008 – 2010 194
Stepwell 2006 – 2010 12844
Trunk 2006 – 2010, 2014 – 2016 6411
High Beam and Low Beam Headlight 2011 – 2013 D1S
Front Fog Light 2011 – 2013 H8
Back Up Light 2011 – 2016 921
Brake 2011 – 2016 H21W
Dome Light 2011 – 2016 194
Front Turn Signal 2011 – 2013 PY24NA
Interior Door 2011 – 2016 194
Map Light 2011 – 2016 12961
Trunk 2011 – 2016 6411
High Beam and Low Beam Headlight 2012 – 2015 D1S
Back Up Light 2012 – 2015 PW16WHTR
Brake 2012 – 2015 PW24WHTR
Dome Light 2012 – 2015 194
Luggage Compartment 2012 – 2015 194
Interior Door 2012 – 2015 194
Map Light 2012 – 2015 12961
Low Beam Headlight 2010 – 2011 D1S
High Beam Headlight 2010 – 2011 H7
Front Fog Light 2010 – 2011 H8
Back Up Light 2010 – 2011 921
Dome Light 2010 – 2011 194
Front Turn Signal 2010 – 2011 PY24NA
License Plate 2010 – 2011 6418
Luggage Compartment 2010 – 2011 6411
Courtesy 2010 – 2011 194
Map Light 2010 – 2011 12961
High Beam and Low Beam Headlight 2012 – 2017 D1S
Back Up Light 2012 – 2017 PW16WHTR
Brake 2012 – 2017 PW24WHTR
Dome Light 2012 – 2017 194
Luggage Compartment 2012 – 2017 194
Interior Door 2012 – 2017 194
Map Light 2012 – 2017 12961
Low Beam Headlight 2010 – 2011 D1S
High Beam Headlight 2010 – 2011 H7
Front Fog Light 2010 – 2011 H8
Back Up Light 2010 – 2011 921
Dome Light 2010 – 2011 194
Front Turn Signal 2010 – 2011 PY24NA
License Plate 2010 – 2011 6418
Luggage Compartment 2010 – 2011 6411
Courtesy 2010 – 2011 194
Map Light 2010 – 2011 12961
High Beam and Low Beam Headlight 2014 – 2016 D1S
Back Up Light 2014 – 2016 921
Dome Light 2014 – 2016 194
Front Turn Signal 2014 – 2016 PY24NA
Interior Door 2014 – 2016 194
Map Light 2014 – 2016 12961
Trunk 2014 – 2016 6411
High Beam and Low Beam Headlight 2011 – 2013 D1S
Front Fog Light 2011 – 2013 H8
Back Up Light 2011 – 2016 921
Brake 2011 – 2016 H21W
Dome Light 2011 – 2016 194
Front Turn Signal 2011 – 2013 PY24NA
Interior Door 2011 – 2016 194
Map Light 2011 – 2016 12961
Trunk 2011 – 2016 6411