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 Headlight 2005, 2010 – 2011 H11
High Beam Headlight 2005, 2010 – 2011 9005
Front Fog Light 2005, 2010 – 2011 H3-55W
Back Up Light 2005, 2010 – 2011 3157
Daytime Running Light 2005 3757NA
Dome Light 2005 212-2
2010 – 2011 PC168
Front Side Marker 2005, 2010 – 2011 194
Front Turn Signal 2005, 2010 – 2011 3757NA
License Plate 2005, 2010 – 2011 194
Parking Light 2005, 2010 – 2011 3757NA
Rear Side Marker 2005, 2010 – 2011 12961
Center High Mount Stop Light 2005 PC168
Courtesy 2005, 2010 – 2011 912
Map Light 2005, 2010 – 2011 PC168
Trunk 2010 – 2011 211-2
Low Beam Headlight 2005, 2010 – 2011 D1S
High Beam Headlight 2005, 2010 – 2011 9005
Front Fog Light 2005, 2010 – 2011 H3-55W
Back Up Light 2005, 2010 – 2011 3157
Daytime Running Light 2005 3757NA
Dome Light 2005 212-2
2010 – 2011 PC168
Front Side Marker 2005, 2010 – 2011 194
Front Turn Signal 2005, 2010 – 2011 3757NA
License Plate 2005, 2010 – 2011 194
Parking Light 2005, 2010 – 2011 3757NA
Rear Side Marker 2005, 2010 – 2011 12961
Center High Mount Stop Light 2005 PC168
Courtesy 2005, 2010 – 2011 912
Map Light 2005, 2010 – 2011 PC168
Trunk 2010 – 2011 211-2
Low Beam Headlight 2006 – 2009 H11
High Beam Headlight 2006 – 2009 9005
Front Fog Light 2006 – 2009 H3-55W
Back Up Light 2006 – 2009 3157
Daytime Running Light 2008 – 2009 3157
2006 – 2007 3757NA
Dome Light 2006 – 2009 212-2
Front Side Marker 2006 – 2009 194
Front Turn Signal 2006 – 2009 3757NA
License Plate 2008 – 2009 12961
2006 – 2007 194
Parking Light 2006 – 2009 3757NA
Rear Side Marker 2006 – 2009 12961
Center High Mount Stop Light 2006 – 2007 PC168
Courtesy 2006 – 2009 912
Map Light 2006 – 2009 PC168
Low Beam Headlight 2006 – 2009 D1S
High Beam Headlight 2006 – 2009 9005
Front Fog Light 2006 – 2009 H3-55W
Back Up Light 2006 – 2009 3157
Daytime Running Light 2008 – 2009 3157
2006 – 2007 3757NA
Dome Light 2006 – 2009 212-2
Front Side Marker 2006 – 2009 194
Front Turn Signal 2006 – 2009 3757NA
License Plate 2008 – 2009 12961
2006 – 2007 194
Parking Light 2006 – 2009 3757NA
Rear Side Marker 2006 – 2009 12961
Center High Mount Stop Light 2006 – 2007 PC168
Courtesy 2006 – 2009 912
Map Light 2006 – 2009 PC168
Low Beam Headlight 2006 – 2009 D1S
High Beam Headlight 2006 – 2009 9005
Front Fog Light 2006 – 2009 H3-55W
Back Up Light 2006 – 2009 3157
Daytime Running Light 2006 – 2009 3157
Dome Light 2006 – 2009 212-2
Front Side Marker 2006 – 2009 194
Front Turn Signal 2006 – 2009 4157NA
License Plate 2006 – 2009 12961
Parking Light 2006 – 2009 4157NA
Rear Side Marker 2006 – 2009 12961
Courtesy 2006 – 2009 912
Map Light 2006 – 2009 PC168
Low Beam Headlight 2008 – 2009 H11
High Beam Headlight 2008 – 2009 9005
Front Fog Light 2008 – 2009 H3-55W
Back Up Light 2008 – 2009 3157
Daytime Running Light 2008 – 2009 3157
Dome Light 2008 – 2009 212-2
Front Side Marker 2008 – 2009 194
Front Turn Signal 2008 – 2009 3757NA
License Plate 2008 – 2009 12961
Parking Light 2008 – 2009 3757NA
Rear Side Marker 2008 – 2009 12961
Courtesy 2008 – 2009 912
Map Light 2008 – 2009 PC168
Low Beam Headlight 2008 – 2009 D1S
High Beam Headlight 2008 – 2009 9005
Front Fog Light 2008 – 2009 H3-55W
Back Up Light 2008 – 2009 3157
Daytime Running Light 2008 – 2009 3157
Dome Light 2008 – 2009 212-2
Front Side Marker 2008 – 2009 194
Front Turn Signal 2008 – 2009 3757NA
License Plate 2008 – 2009 12961
Parking Light 2008 – 2009 3757NA
Rear Side Marker 2008 – 2009 12961
Courtesy 2008 – 2009 912
Map Light 2008 – 2009 PC168