Sennheiser Set SET 820 Instruction Manual page 17

Accessories
Only use original Sennheiser spare parts and accessories.
ATTENTION: Components from other manufacturers (e.g. for power supply
or battery) may cause damage to the unit and will invalidate
the warranty.
The following accessories are available from your authorized dealer:
Rechargeable battery
Charger
Stethoset receiver
Clip-on receiver with audio socket
Transmitter
External microphone
BA 151
L 151-2
RR 820
RR 820 S
TR 820
MKE 800 TV
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