IWC 401BrandIWCCaliber401Size10FunctionVersionHandsStem6338Stem (subs.)Stem (2 pce)Balance staff30020Balance staff (subs.)Mainspring (subs.)Mainspring (subs.)BatteryWatchpartsPart NocaliberdescriptionoriginalArtno.275Sweep second pinion94200275C853401Winding stem8026338723Balance staff ST -shock-absorber80230020770B (=IWC 401Mainspring94200770401