I bought these LED marker lights from AUXITO to replace all four defective 2008 F-350 OEM Dully fender lights. The LED’s are slightly crisper and brighter which is a plus. Install is of course very easy, just plugging the pigtail into the factory light socket. I decided to tape up the connection really well but it's probably not too necessary. They do take a little getting used to as far as visually because they are not as flush looking like factory.. they are pretty tall little bubbles on the fenders but they do look great once you get used to them. LED’s are polarity dependant so be sure to check the LED leads with each set of the 2 OEM Wire’s each outlet. If you wire backwards you will wrongly think the light is no good. If after installation you think “these lights are a little too bright in your side rear view mirrors at night”, I suggest you aim those side view mirrors at the rear side traffic instead of at the fenders.