Neovivid Solid Brass Sextant Nautical Maritime Astrolabe Marine Material : Brass, Finish : Antiquated Brass Mariners and surveyors used sextants to calculate latitude and longitude to navigate and explore Handmade replica! Size is 3 inches approx. It can be used for basic measurements. Great table top item for office, home and a unique gift. A free brass keyring is sent along as a gift.