it is the same light but the lens is slightly different. Apparently the FF stand for free form (i think cant remember exactly) basically it is a crystal clear lens (like on our headlights and most lights these days. The regular 500s are kinda frosted like headlights on older cars used to be. I have both, the regular ones on the Jeep and the FF on the 4Runner. I like the FF better cause they look shinier and cleaner, but you can see the bulb real easy which is kinda weird. The regular ones aren't bad though either. if you are in the store, pull both out and look at them and see which one you like better.