I had to replace my old nasty gross looking yellowed headlight assemblies so I decided to go all the way and get these LED headlight bulbs too. Going from what I had to these is such a dramatically amazing difference. They light up the road, signs and the reflectors in the street so brightly it's like a video game.They look great on my old truck giving it a refreshed modern look and even with the daytime running lights which are reduced power I can still tell they are on in the daytime. All I can say is WOW! I am ordering the high beams and fog lights next just to be thorough and do it right. I honestly don't see a real use for needing my fog lights with these headlights, they are plenty bright. As for the high beams, pretty much the same thing. All I can say, if the high beams work like these low beams then anyone coming at me with their high beams on is going to see nothing but purple and yellow dots for 15 minutes after I flash them with my complaint. I'll probably look like a shooting star zipping down the highway.NOTE, PAY ATTENTION!: These bulbs are directional! They are flat not round, hence they have to be installed PROPERLY for maximum illumination. Since I wasn't sure in my application which direction the flat side should be I installed one horizontally and the other facing vertically. On my 2005 Trailblazer EXT, the PROPER way was horizontally, LED's pointing left to right. Vertically the light just splatters all over the place and does not focus properly on the road. I called customer service to confirm and they are SUPER NICE and helpful! The nice thing is you don't have to pull apart your assembly and turn the retaining ring, these come with a torx screw that you can loosen and turn it to the position you wish. It comes with instructions on how to do this. So if your lights scatter rather than focus properly then the bulbs aren't to blame, it's the installer and you didn't read the directions!These new bulbs also have the fans which when putting on the dust caps do stick out enough to touch them. I also confirmed with customer service that this is okay as long as the fan can spin. Since these seal well you really don't NEED the dust covers but will work either way. The fan blows the air toward the LED to cool the LED not the housing so no risk of frying your bulbs if you use the dust caps. The nice lady in customer service did offer to exchange them for a lower profile set that won't stick out so far if I wanted to go that route. I'm happy with these for now but I appreciated the offer. I love how they stand behind their product and I will only be using Alla in the future for the rest of this truck and for my 2001 Tahoe which is next.