H11A vs H11B

It's important to select the right version of HID, but which one do you need?

Why does it matter?

Because HID has a return wire by design, this wire can interfere with the beam from your headlight projector or reflector. But why does it matter, can I just get H11? Unfortunately it's not that easy, and the reason is due to the difference between Halogen and HID. Halogen simply put does not have the return wire, so it does not matter. Once you upgrade to HID, you need to ensure you pick up the right version.

So do I need A or B

*image provided by Morimoto

Most main/low beam Projector style headlights use H11B with the exception of Kia/Hyundai, they normally use H11A, and Reflector style headlights normally use H11A.

Typically in a Reflector style headlight, the return wire would be facing down (on the bottom) in the low beam, and up (on the top) for the high beam. In a Projector, the return wire would normally be facing down. 

H11A is considered the opposite, but it really depends on your vehicle. H11B is also referred to as H11. You'll need to remove your original Halogen bulb, and see which way tabs are facing. Alternatively, you can do some searching online for your vehicle, as every make and model is different. Since HID conversion are so popular, there is bound to be somebody else out there asking the same question, such as on automotive forums.

Additional Resources
In case you are still lost, here are a few links with more information:
TRS Video

If you have any further questions please drop us a line.