SEFRAM MW9520 Manuel D'utilisation page 58

(2) Cleaning and storage:
WARNING
To avoid electrical shock or damage to the
instrument, do not get water inside the case.
Periodically wipe the case with a damp cloth and
detergent. Do not use abrasives or solvents.
If the instrument is not to be used for more than 60
days, please remove the batteries for storage.
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