Weems & Plath gyro compass. We know very little about this little beauty other than that it looks very expensive? I spent 2 weeks at the Sperry Gyro Compass school in San Francisco when I was attending the Maritime Academy a half century ago. The only thing that I remember is that these complicated gadgets point TRUE NORTH and you don't have to make corrections to them for deviation and variation. Seems like a lot of trouble to save some simple adding and subtracting? In our endless quest at keeping boating AFFORDABLE we've priced this little jewel at $495.00.