Zte -G R221 User Manual page 9

Do not drop, knock or harshly treat the phone. Rough handling
can break internal circuit boards.
Do not connect the phone with any incompatible enhancement.
Do not attempt to disassemble the mobile phone or battery.
Do not store the phone with flammable or explosive articles.
Do not charge the mobile phone without battery.
Some electronic devices are susceptible to electromagnetic interference
sent by phone if inadequately shielded. Please use phone at least 20
cm or as far away as you can from TV set, radio and other automated
office equipment so as to avoid electromagnetic interference.
Operating phone may interfere with medical devices like hearing aides
and pacemakers, or other medical devices in hospital. Consult a physician
or the manufacturer of the medical device before using phone.
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.
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