This is a rare IWC Calatrava with Waterproof case also called 'Hermet'. Made in the 40's it featurea a classic Calatrava style steel case with screwback and measures 31mm excl the special original crown. The original military style dial features explorer/sector radium indexes and has aged in a lovely green tone. Movement is IWC's Cal 83 which is working nicely. Attached is an original period G&F bamboo bracelet. Rare IWC Hermet for the connaisseurs...