Hour Window (Utc Or Umt Indication); Chronometer Certificate - Ball NM2038 Owner's Manual

14. 24-Hour Window (UTC or UMT Indication)

MODELS: GM1020, NM1092, NM2092
The Trainmaster Cleveland Express Dual Time (GM1020) and Fireman
Night Train (NM1092) share a 24-hour indicator at 11 o'clock. This
indication is tied to the main time zone and thus shows 24-hour UTC or
UMT time.
• Time setting: At position [1], the second hand is stopped. Turn the crown
forward to set the local time, ensuring that the 24-hour window properly
displays day or night.
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15. Chronometer Certificate

MODELS: CM1010, CM2098, CM3188, DC3026, DG2016, DL2016,
DM1022, DM2036, DM2076, DM2136, DM2176, DM3000, DM3108,
GM1020, GM1032, GM1050, GM2020, GM2026, GM2098, NM1020,
NM1022, NM1036, NM1038, NM1058, NM1098, NM2026, NM2028,
NM2198, NM3022, NM3060, NM3888, NT3888
(following only applies to above model numbers with letter "C" in middle
group of digits, e.g. DM3000A-SCA-BK)
A chronometer is an extremely accurate watch. It takes its name from
the Greek words chronos + metron meaning "to measure time". A BALL
chronometer is a highly accurate, mechanical watch whose precision has
been tested and verified by the Official Swiss Chronometer Testing Institute
(Contrôle Officiel Suisse des Chronomètres, or COSC, in French).
Before issuing the certificate, the COSC conducts elaborate precision tests
on each BALL movement using cameras and computers and analyzes the
data. The COSC performs seven different tests. Failure to meet the minimum
standard in any one of the tests means that a movement is rejected. Here is
a brief summary of the testing procedures:
※ Test 1
Mean daily rate: After 10 days of tests, the mean daily rate of the movement
must be within the range of -4 to +6 seconds per day. The COSC determines
the mean daily rate by subtracting the time indicated by the movement 24
hours earlier from the time indicated on the day of observation.
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