IWC. A Limited Edition titanium automatic calendar wristwatch Aquatimer '35 Years Ocean 2000' , Ref IW329101, Circa 2017IWC. A Limited Edition titanium automatic calendar wristwatchModel: Aquatimer '35 Years Ocean 2000' Reference: IW329101Date: Circa 2017Movement: 21-jewel Cal.30120 automaticDial: Black, applied luminous baton hour markers, white outer minute divisions, revolving inner bezel, date aperture at 3, luminous baton hands, centre secondsCase: Brushed round, screw down back, No.6075631Strap/Bracelet: Detachable black IWC rubberBuckle/Clasp: Signed titanium buckleSigned: Case, dial & movementSize: 42mmIWC first produced the Aquatimer in 1966/67 as a diver's watch for the new fashion of underwater diving for sport. As well as having a Master Compressor case enabling it to be water resistant to 20 Atmospheres it had the innovation of twin water-resistant crowns, the second turning the calibrated internal bezel. This keeps the watch safe from being accidently knocked out of position and leading to miscalculated dive times.The current lot was released in 2017 in a limited edition of 350 pieces.