What is difference single filament VS double filament?
 

Turn signals are same price but one is single and the other is double. What are the pros vs cons

Thanks

Double filament can be used for running lights and signals. Single will only serve as signals.

Plus, you need to have the wiring in place to be able to use both filaments and the bulb socket has to be made for it.

http://forums.themustangsource.com/a...ment-bulbs.jpg