Zte Grand X In User Manual page 326

Absorption Rate, or SAR. The SAR limit for mobile devices is
2 W/kg and the highest SAR value for this device when tested
was 0.572 W/kg. As mobile devices offer a range of
functions, they can be used in other positions, such as on
the body as described in this user guide.
As SAR is measured utilizing the device's highest transmitting
power, the actual SAR of this device while operati ng is
typically below that indicated above. This is due to
automatic changes to the power level of the device to ensure it
only uses the minimum power required to communicate with
the network.
Body Worn Operation
Important safety information regarding radio frequency
radiation (RF) exposure:
To ensure compliance with RF exposure guidelines the
phone must be used with a minimum of 15 mm separation
from the body.
Failure to observe these instructions could result in your RF
exposure exceeding the relevant guideline limits.
Limiting Exposure to Radio Frequency (RF)
Fields
For individuals concerned about limiting their exposure to RF
fields, the World Health Organization (WHO) provides the
following advice:
326