This small brass porthole with iron hatch cover has a 10 inch frame with 6 inch glass. The glass is heavy original glass and has minor surface scratches. This small brass porthole with iron hatch cover has a single closure dogs that work freely. The outside frame has 6 mounting holes. The back side of the frame has a flange ring that extends out 1/4 of an inch and is 6 1/4 wide (measured from the outside edge of the outside edged of the ring. The total thickness of this porthole measured from the back edge of the flange to the top of a closure dog is 4 1/2 inches. The window is non-opening, but the steel hatch cover opens and closes freely.