Sennheiser Set 810 Notice D'emploi page 29

Additional information
This system uses infrared light which is emitted by the transmitter and
received by the stethoset receiver. Please note that infrared light emitted by
other light sources may interfere with the useful signal of the SET 810. If the
light path between transmitter and receiver is obstructed by clothing such as
scarves etc., the reception may also be disturbed.
Varnish or furniture polish may degrade the rubber feet of the transmitter.
Place the transmitter on a nonslip pad to avoid potential staining of
furniture.
Delivery includes a pair of replacement ear pads. If necessary, remove the old
ear pads and slide on the new ones.
Use a soft cloth for cleaning the units. Do not use abrasive cleaners.
According to today's scientific knowledge, the infrared light emitted by this
unit is not harmful to humans or animals.
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