Collapsible brass spyglass made to store away as small as possible. This is a marvel of hand tooled telescoping brass tubes. Pull out all the way and focus by adjusting the smallest eye section.
Feel like a sea captain scanning the horizon from a heaving aft deck. This is a classic explorer and navigator tool. Before GPS, before shortwave radio, radar, etc. - to find your way you needed a compass, a sextant and a telescope.