this is an iwc from the early 1970s with rare tuning fork movement, the technic that was used for only a short period before quartz came out. the second hand of a tuning fork watch runs in a comparable constant way as one from a manually powered movement. A typical silent humming sound can be realized, when you listen closely on the movement. this iwc feautures a 37x 41mm steelcase and the IWC Kaliber 150 which is running exactly in time- and datefunction. dial and hands are flawless and all parts about the watch are still the original ones. the piece with important historic technic and beautiful wrist appearance comes on a new green leatherband.