A Fine Stainless Steel Oversized Openface Deckwatch with Guillaume Balance and Power Reserve, Ulysse Nardin, Locle, Suisse, Chronometre, No. 124718, Circa 1940

gilt lever movement, bimetallic two-arm Guillaume Balance, cam-wheel regulator, steel cuvette, white enamel dial, large Roman numerals, large blued steel spade hands, large subsidiary seconds, power reserve at 12 o'clock, massive polished stainless steel case with slide and receptor for external timing and amplification device, screw back, large circular bow, cuvette numbered, case, dial and movement signed. 

Originally this watch could have been connected to an external box for amplification and timing. Once the slide at 6 o'clock is pushed, the receptor at 9 o'clock sends out a loud ticking sound to the box, which can be used to make timing easier. Unfortunately, the present lot no longer has this box.