Vintage Brass Porthole

Nautical marine 2 dog lock, solid, heavy brass Porthole. Outside diameter measures approximately 15", Glass is 10" across and opening is 11". Printed on glass is Armour Plate. Armour Plate Glass only is also etched into the outer brass sleeve and what appears to be the letter Z and numeral 9 are etched on a post. This definitely has some age to it so it's not one of those cheap, chinese re-productions. There are numerous indentions and what looks like an old gasket on the backside, several scratches on glass nothing major and still looks great, also brass could be cleaned up but I'll leave that up to the new owner.