Folks use these in many creative ways; one favorite being a nautical beach theme picture frame.
Overall solid brass housing measures 15 inches across in diameter. Depth is about 1/2" except where porthole clamps are at 3" tall. Weight 7 lbs.
Glass portion is 9-1/4" across in diameter. When fully functional porthole is opened, there is a circular space of 11-7/8" across in diameter.
Glass is easily removable (see photo of backside) to use as a pass-through porthole etc.
Three countersunk screw holes for mounting (under clamps and hinge areas so hidden from view). Nine brass rivets are beautiful accents. Brand new and packaged very well for transit.