Beurer HA 85 Pair Mode D'emploi page 19

4. Check whether you have selected the correct size of earplug by
moving your head slowly up and down and then left and right while
opening and closing your jaw. If the earplug slips out, it is too small.
If you wear glasses, place the arm of the glasses between your head
and the hearing amplifier.
CAUTION
Never insert the sound tube into the ear canal without an earplug. Make
sure also not to press the tube and earplug too deeply into the ear canal.
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