Lenovo A850 Important Product Information Manual page 19

Specific Absorption Rate information
efficiency and to minimize interference on the network, the operating
power of your mobile devices is automatically decreased when full power
is not needed for the call. The lower the power output of the device, the
lower its SAR value.
To meet RF exposure guidelines during body-worn operation, the device
must be positioned at least 1.5cm away from your body.