Unusual Antique Brass Cased Compass

This lovely, good quality, antique brass cased compass with a manual activated transit lock on the side, is in great condition, with a nice patina to the brass and it appears to be working well. It has an unusual, small round glass window in the hinged lid, along with an unusual large brass top ring, featuring a tiny peep hole. The glass window and bevelled glass top is clear and undamaged, and the snug fitting lid clicks shut. It has a diameter of 5cm, a width of 1,7cm, measures 8,5cm with hanger and weighs 94,4g.