Omega SA 1538, 2520, 2500, 1120 Days Position Temperature 23C, Days 14,15 Position Temperature 23C

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U	Precision tolerances

Omega mechanical watches with a certified chrono- meter movement

Omega watches bearing the chronometer inscription (in accordance with the certificate issued by your autho- rised Omega retailer) are high-precision timepieces that have passed the precision tests of the Official Swiss Chronometer Testing Institute (Contrôle Officiel Suisse des Chronomètres, COSC).

This neutral and independent body individually tests each movement for 360 consecutive hours, during which it is placed in the five common wrist positions and exposed to three different temperatures.

Days	1,2	3,4	5,6	7,8	9,10
Position
Temperature	23°C	23°C	23°C	23°C	23°C
Days	11	12	13	14,15
Position
Temperature	8°C	23°C	38°C	23°C

To earn the title of chronometer, the mechanical move- ment’s average daily variation in rate must be between –4/+6 seconds per day, or a precision of 99.99%, the highest precision attainable by a mechanical movement.

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Contents

Operating Instructions Viii Xviii Contents What are the service intervals? Special recommendationsEnvironmental protection Leather strapsAnti-reflective treatment Screw-in crownOmega International Warranty Valid for U.S.A. onlyOmega SA Rue Stämpfli 96, 2500 Bienne Omega International Warranty Above manufacturer’s warranty Quartz Watch Calibres 1376, 1456 figCalibres 1426, 1530, 1532 fig Calibres 1424, 1538 figCalibre 4000 fig. IIbis Time setting by pressing the correctorCalibres 1424 Quartz chronograph Calibre 1270 figWatch functions Chronograph functionsPusher B Reset CalibreSimple timing function crown in position Pusher a Start stop read timeAddition function crown in position Pusher a StartPusher a Stop to read time Pusher a Press again to restart Pusher a StopCalibres 1120, 2500, 2520, 2610 fig 2627 fig. III 2300 fig Power reserve cal Counter at 9 o’clock small secondsManual & Self-winding watch Calibre 2201 Manual-winding Power reserveCrown has 2 positions Pusher B reset after a stop Self-winding chronographCalibres 3205 fig. XV 3220 fig. Xiii 3601 Regatta function calApnea function based on a 14 minute dive Regatta functionApnea function cal Self-winding chronograph with date Calibre 3304 figChanging the date press the corrector C at 10 o’clock Calibre 1151 figSelf-winding split seconds chronograph Watch functions calibreSelf-winding split seconds chronograph Chronograph functions with split secondsManual-winding chronograph Calibres 1861, 1863 fig. XV 1866, 3604 figCalibre 1866-Date and moon phase correction Date setting small counter at 12 oclock press corrector CSetting the hands minutes and seconds Perpetual calendarCalibre 1680 fig ThermocompensationDisplay and correction of the month Display and correction of the yearly cycle Self-winding GMT & GMT Chronograph Calibres 1128 fig. VI 2628 fig 3603 figSelf-winding GMT & GMT Chronograph Coincide with a given time signal Second Time Zone calibre 1128, figBi-directional turning bezel calibre Second Time Zone calibre 2628, fig. VII, calibre 3603, figDays Position Temperature 23C Days 14,15 Position Temperature 23CPrecision tolerances 32 -1 to +6 seconds per dayOther Omega mechanical watches Quartz watchesPressure is gradually increased to Helium escape valveHelium escape valve fig How to use the helium escape valve fig Not functional, since it is screwedExample calculating the speed of a car Using the tachymetric scaleTachymetric scale Rubber strap Rubber strap Adjusting the length Foldover claspsSnap-fastening foldover clasps Opening ClosingClosing fig Adjusting the length figFoldover clasps with pushers Opening fig Pictograms