When doing replacement or upgrading on 2006 – 2018 Mazda MX-5 Miata with capsule daytime halogen headlamps HID lamps LED running without, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight2006 – 2015 H7
High Beam Headlight2006 – 2015 H9
Front Fog Light2006 – 2015 H8/H11/H16
Back Up Light2006 – 2015 921
Brake2006 – 2015 7443
Dome Light2006 – 2015 DE3175
Front Side Marker2006 – 2015 194
Front Turn Signal2006 – 2008 7440NA
2009 – 2015 7444NA
License Plate2006 – 2008 12961
2009 – 2015 194
Parking Light2006 – 2008 12961
2009 – 2015 7443NA
Rear Turn Signal2006 – 2015 7440NA
Tail Light2006 – 2015 7443
Trunk2009 – 2015 DE3175
Low Beam Headlight2006 – 2015 D2S
High Beam Headlight2006 – 2015 H9
Front Fog Light2006 – 2015 H8/H11/H16
Back Up Light2006 – 2015 921
Brake2006 – 2015 7443
Dome Light2006 – 2015 DE3175
Front Side Marker2006 – 2015 194
Front Turn Signal2006 – 2008 7440NA
2009 – 2015 7444NA
License Plate2006 – 2008 12961
2009 – 2015 194
Parking Light2006 – 2008 12961
2009 – 2015 7443NA
Rear Turn Signal2006 – 2015 7440NA
Tail Light2006 – 2015 7443
Trunk2009 – 2015 DE3175
Back Up Light2016 – 2018 7440
Daytime Running Light2016 – 2018 7440
Dome Light2016 – 2018 DE3175
Front Side Marker2016 – 2018 194
Front Turn Signal2016 – 2018 7444NA
License Plate2016 – 2018 194
Rear Side Marker2016 – 2018 194
Rear Turn Signal2016 – 2018 7440NA
Trunk2016 – 2018 DE3175