When doing replacement or upgrading on 2005 – 2011 Cadillac STS Base Platinum V 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 Headlight2005, 2010 – 2011 H11
High Beam Headlight2005, 2010 – 2011 9005
Front Fog Light2005, 2010 – 2011 H3-55W
Back Up Light2005, 2010 – 2011 3157
Daytime Running Light2005 3757NA
Dome Light2005 212-2
2010 – 2011 PC168
Front Side Marker2005, 2010 – 2011 194
Front Turn Signal2005, 2010 – 2011 3757NA
License Plate2005, 2010 – 2011 194
Parking Light2005, 2010 – 2011 3757NA
Rear Side Marker2005, 2010 – 2011 12961
Center High Mount Stop Light2005 PC168
Courtesy2005, 2010 – 2011 912
Map Light2005, 2010 – 2011 PC168
Trunk2010 – 2011 211-2
Low Beam Headlight2005, 2010 – 2011 D1S
High Beam Headlight2005, 2010 – 2011 9005
Front Fog Light2005, 2010 – 2011 H3-55W
Back Up Light2005, 2010 – 2011 3157
Daytime Running Light2005 3757NA
Dome Light2005 212-2
2010 – 2011 PC168
Front Side Marker2005, 2010 – 2011 194
Front Turn Signal2005, 2010 – 2011 3757NA
License Plate2005, 2010 – 2011 194
Parking Light2005, 2010 – 2011 3757NA
Rear Side Marker2005, 2010 – 2011 12961
Center High Mount Stop Light2005 PC168
Courtesy2005, 2010 – 2011 912
Map Light2005, 2010 – 2011 PC168
Trunk2010 – 2011 211-2
Low Beam Headlight2006 – 2009 H11
High Beam Headlight2006 – 2009 9005
Front Fog Light2006 – 2009 H3-55W
Back Up Light2006 – 2009 3157
Daytime Running Light2008 – 2009 3157
2006 – 2007 3757NA
Dome Light2006 – 2009 212-2
Front Side Marker2006 – 2009 194
Front Turn Signal2006 – 2009 3757NA
License Plate2008 – 2009 12961
2006 – 2007 194
Parking Light2006 – 2009 3757NA
Rear Side Marker2006 – 2009 12961
Center High Mount Stop Light2006 – 2007 PC168
Courtesy2006 – 2009 912
Map Light2006 – 2009 PC168
Low Beam Headlight2006 – 2009 D1S
High Beam Headlight2006 – 2009 9005
Front Fog Light2006 – 2009 H3-55W
Back Up Light2006 – 2009 3157
Daytime Running Light2008 – 2009 3157
2006 – 2007 3757NA
Dome Light2006 – 2009 212-2
Front Side Marker2006 – 2009 194
Front Turn Signal2006 – 2009 3757NA
License Plate2008 – 2009 12961
2006 – 2007 194
Parking Light2006 – 2009 3757NA
Rear Side Marker2006 – 2009 12961
Center High Mount Stop Light2006 – 2007 PC168
Courtesy2006 – 2009 912
Map Light2006 – 2009 PC168
Low Beam Headlight2006 – 2009 D1S
High Beam Headlight2006 – 2009 9005
Front Fog Light2006 – 2009 H3-55W
Back Up Light2006 – 2009 3157
Daytime Running Light2006 – 2009 3157
Dome Light2006 – 2009 212-2
Front Side Marker2006 – 2009 194
Front Turn Signal2006 – 2009 4157NA
License Plate2006 – 2009 12961
Parking Light2006 – 2009 4157NA
Rear Side Marker2006 – 2009 12961
Courtesy2006 – 2009 912
Map Light2006 – 2009 PC168
Low Beam Headlight2008 – 2009 H11
High Beam Headlight2008 – 2009 9005
Front Fog Light2008 – 2009 H3-55W
Back Up Light2008 – 2009 3157
Daytime Running Light2008 – 2009 3157
Dome Light2008 – 2009 212-2
Front Side Marker2008 – 2009 194
Front Turn Signal2008 – 2009 3757NA
License Plate2008 – 2009 12961
Parking Light2008 – 2009 3757NA
Rear Side Marker2008 – 2009 12961
Courtesy2008 – 2009 912
Map Light2008 – 2009 PC168
Low Beam Headlight2008 – 2009 D1S
High Beam Headlight2008 – 2009 9005
Front Fog Light2008 – 2009 H3-55W
Back Up Light2008 – 2009 3157
Daytime Running Light2008 – 2009 3157
Dome Light2008 – 2009 212-2
Front Side Marker2008 – 2009 194
Front Turn Signal2008 – 2009 3757NA
License Plate2008 – 2009 12961
Parking Light2008 – 2009 3757NA
Rear Side Marker2008 – 2009 12961
Courtesy2008 – 2009 912
Map Light2008 – 2009 PC168