One of the first things I did with my XF when I got her. Two sets of H-7 SS Ultra's. Super bright, and have yet to replace any of them. I keep hearing about SS not lasting long, same with SS Ultra's (they even have something about that on the rear card of the twin packs). I think it may be simply (DO NOT) let your fingers or anything touch the glass lamp module as you install them. They generate so much heat, hot spots develop. Hot spots on high power bulbs can severely limit its lifespan. When I bought my 01 Ranger (edge) truck back on 03 I put a set of them SS Ultra's in it. They are still performing SUPER. I even had to replace both headlight assemblies once, but not the SS Ultra's. I love em, and have em in all my vehicles.