An English fusee chronometer with helical hairspring in a silver open face case. Gilt three quarter plate keywind movement with fusee and chain, Harrison's maintaining power. Engraved cock with diamond endstone. Freesprung compensation balance with helical blue steel hairspring. Earnshaw type spring detent chronometer escapement, screwed in jewelling, escape pivots with endstones. Off white enamel dial marked “Chronometer”, subsidiary seconds, Roman numerals, blue steel seconds hand, gilt hands. Plain silver open face case, maker's mark “W.B” in a rectangle and number corresponding to that on the movement.