Sennheiser SD series User Manual page 4

Important safety information
Safety instructions for Lithium-Polymer rechargeable batteries
In extreme cases, abuse or misuse of rechargeable batteries can lead to:
WARNING
• explosion,
• fire development,
• heat generation or
• smoke/gas development.
Switch rechargeable
battery-powered
products off after use.
Only charge
rechargeable
batteries at ambient
temperatures
between 10°C/50°F
and 40°C/104°F.
Dispose of defective
products with built-in
rechargeable batteries
at special collection
points or return them to
your specialist dealer.
Do not heat above 70°C/158°F,
e.g. do not expose to sunlight
or throw into a fire.
When not using rechargeable
batteries for extended periods
of time, charge them regularly
(about every 3 months).
Only use rechargeable batteries
recommended by Sennheiser
and the appropriate chargers.
SD Series - User Guide | 3