This is an authentic replica of the pocket glass of a boatswain. With this tool the officer in charge would measure a ship’s speed, count knots and count 3 minutes. Marine sand glasses were the most dependable measurement of time while at sea, and used well into the 19th century.
Re-enact your own naval adventure, or share a small gift with a big presence. Measures approximately 3.5 inches tall.
(What is a boatswain? How fast is a knot? Educational opportunities, that's what!)