those are Athena calipers. i have one on the front of my bike, and i personally think they're the prettiest brake calipers ever made. theres two versions of Athenas, those, like mine are the earlier version i believe. later (?) they went to a monoplaner design.
actually i think they only did these for a few years and i don't think you see too many around. they work great by the way, i'm using te og pads on some and they stop on a dime.