Suunto LUMI User Manual page 41

NOTE: The markings on the cover may be left unaligned once the cover has
been tightened. If the old cover is undamaged, it does not need to be replaced.
NOTE: If the threads of the battery compartment cover are damaged, send
your device to an authorized Suunto representative for service.
NOTE: Replace the battery with extreme care to ensure that your Suunto Lumi
remains water resistant. Careless battery replacement may void the warranty.
NOTE: Heavy use of the backlight will significantly reduce battery life.
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