Denver Electronics BTH-251 Manual De Instrucciones página 6

Caution:
1. Please avoid very high volume for a constant period of time. This may
damage your hearing.
2. If not used for a long time, make sure to charge it once every 6 months. 3.
Battery is built-in and it is not replaceable.
3. Please keep the headset away from wet areas. Do not use in rain or moist
weather.
4. The operating temperature is 5°C to 35°C. Please don't put the headset
into fire to avoid battery blast accident.