Zte R621 User Manual page 9

 Be aware of the usage limitation when using phone at places such as
oil warehouses, or chemical factories, where there are explosive
gases or explosive products being processed, because even if your
phone is in idle state, it still transmits radio frequency (RF) energy.
Therefore, power off your phone if required.
 Do not touch the antenna while calling. Otherwise it will affect the
quality of calling and waste battery energy. The damaged antenna
will cause slight burn while touching your skin.
 Keep phone out of the reach of small children. Phone may cause
injury if used as a toy.
 Do not put other things on the terminal to avoid overlaying radiator.
 Keep the antenna free from obstructions and position the antenna
straight up. This will ensure best call quality.
Precautions for Potentially Explosive Atmospheres
 Switch off your phone prior to entering any area with potentially explosive
atmospheres, such as fueling areas, fuel or chemical transfer or
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