I’ll go for the direct answer 
“Festoon” is the shape of the bulb. It’s basically a rectangular bulb/LED with a connector on each end.
“CANBUS Error Free” means that it has a little resistor in it so that it doesn’t trip your smart’s rapid turn signal flash.
So, if you’re replacing the license plate lights, you’re going to want a festoon CANBUS LED.
I recommend getting CANBUS in every LED. In my experience, even if the smart detects too little resistance in the license plate lights it’ll trigger the rapid flash.
“Festoon” is the shape of the bulb. It’s basically a rectangular bulb/LED with a connector on each end.
“CANBUS Error Free” means that it has a little resistor in it so that it doesn’t trip your smart’s rapid turn signal flash.
So, if you’re replacing the license plate lights, you’re going to want a festoon CANBUS LED.
I recommend getting CANBUS in every LED. In my experience, even if the smart detects too little resistance in the license plate lights it’ll trigger the rapid flash.
