This compass is suitable for use as a landing compass for checking small ships and aircraft compasses. It also can be used as a classic hand-bearing boat compass.
Text on the compass: Henry Browne &son Ltd. Trade " Sestrel " mark. Barking & London
The compass is manufacture mostly from non-magnetic brass and liquid filled to provide card damping over a wide temperature range. A large high quality prism is used to magnify the card reading and accurate headings are taken through the prism sight line, a sight wire located above the compass card and the object being observed.