You are bidding on a GOOD used example of a WW2 Japanese Army / Navy Seikosha Phonotelemeter (Acoustic Distant) Stopwatch! Brought back by a US Servicemen, this was intended for use with Artillery Pieces, as well as Torpedo Boats and Submarines!This stopwatch was used to measure time intervals with the difference in velocity between light (300,000 km/sec) and sound (300 m/sec).Most commonly used for artillery range finding, the bearer would measure the time difference between the 'flash' and the 'bang' produced by an artillery discharge.This calculation was then used to accurately calculate the target's distance.These were used for long-range targeting as well as on board torpedo boats and submarines to measure torpedo running time.Complete in the original box, this Seikosha Phonotelemeter is in DECENT used condition! The manufacture name is clearly marked on the face, and was manufactured between 1939 and 1945. 'Phonotelemeter' is printed in Latin characters on the porcelain dial (which is normal for this type of watch), and all writing is clearly legible. There is some slight wear overall, and both the back and front have damage (crystal is cracked, and rear cover has been sheared off). Nonetheless it is in 100% FUNCTIONING condition!It comes complete in the original wood storage box, with the Kanji writing indicating the manufacture of 'KH' (K. Hattori) on the inside cover, as well as 'East Tokyo Navy Base' – so this is a Navy property item. The Kanji on the top of the box indicates, 'Acoustic Distance Meter'. Movement is 100% functional, as mentioned, however this is probably only good for parts/restoration.Like most Japanese items, it is a VERY RARE item, PERFECT for any collection, or display!