The Ultralight line is Leupold's new name for what were previously called Compacts.
That 4x28 "rimfire" is a trim little scope, actually about 3.5x. It used to be offered as the 4x28 Compact for centerfires, with a slightoly different parallax setting, but eventually not many people were buying them under that name. I used one on my .375 H&H on my first safari, and it worked very well.
