1973 IWC Large Vintage Mens Caliber 150 Electronic Tuning Fork Watch - Stainless Steel Titanium and stainless steel Case markings (outside): Waterproof with

Case markings (outside): Waterproof with hypocampus logo

Dimensions: 21mm x 28mm

It's powered by the Albert Pellaton designed automatic Caliber 8531 movement

and IWC among others to build some of the beautiful examples of their early wristwatch cases

1973 IWC Large Vintage Mens Caliber 150 Electronic Tuning Fork Watch - Stainless Steel Titanium and stainless steel Case markings (outside): Waterproof withToday's offering features this very cool and rare IWC caliber 150 watch. For the movement the company used a patented tuning fork based movement made by ESA. These watches use a battery driven tuning fork whose vibrations are converted by a special index mechanism into an almost smoothless rotary motion of the hands. At the time, tuning fork watches were the most accurate timekeeping mechanisms ever devised. The tuning fork technology was so accurate