Modern roof prisms represent a great compromise to me. They are bigger than some of the shirt pocket glass that Vern is talking about but they are considerably more compact than the large porro prisms of the past. And in my part of the country where we do a lot of glassing, the 7x42/8x43/10x40 has a decided advantage in terms of exit pupil and field of view over the 7x25s and their kin. I'm not the first one to say this, but we are truly living in the good old days when it comes to quality binoculars. Today's middle of the road glass competes on an even footing with the finest European optics of just ten years ago.