Freightliner Classic/FLD chrome plastic dash vent w/frame
With an assist from a flathead screwdriver, it's relatively simple to snap your old vent out. Then, push this one back into its place for instant bling. They might not make your truck any colder or warmer, but they'll certainly make it cooler!
With the exception of the single skinny vent next to the glove box, all of the vents in the Freightliner Classic are this size.