2013 and Older Harley Davidson Motorcycles
If you have a 2013 or older Harley Davidson Touring Model (Street Glide, Road King, Ultra Classic, Switchback or Electra Glide etc.), you will need the adapter ring.
2014 and Newer Harley Davidson Motorcycles
If you have a 2014 - 2017 Softail model, you will not need any additional installation accessories. Does not fit 2018 and newer Softail models.
If you have a 2014 or newer Switchback models will require an adapter ring for the installation.
If you have a 2014 or newer Street Glide or Road King model you will need the Dual Bulb Adapter Harness (899).
If you have a 2014 or newer Harley Davidson Model Motorcycles not listed above, you will need the Single Bulb Adapter Harness (897).
If your motorcycle came with an LED headlight from the factory, you will need the Single Bulb Adapter Harness (897)
2014 and Newer Indian Motorcycles
If you have a 2020 or newer Indian model you will need the IND-H4-MX150 Adapter Harness.