Lenovo A516 Smartphone - Manual (Page 6)

Important safety and handling information
Prevent hearing damage
Lenovo Phone has a headphone connector. Always use the headphone
connector for headphones (also called a headset) or earphones.
CAUTION
Excessive sound pressure from earphones and headphones can cause hearing loss.
Adjustment of the equalizer to maximum increases the earphone and headphone
output voltage and the sound pressure level. Therefore, to protect your hearing,
adjust the equalizer to an appropriate level.
Excessive use of headphones or earphones for a long period of time at
high volume can be dangerous if the output of the headphone or
earphone connectors do not comply with specifications of EN 50332-2.
The headphone output connector of Lenovo Phone complies with EN
50332-2 Sub clause 7. This specification limits Lenovo Phone's
maximum wide band true RMS output voltage to 150 mV. To help protect
against hearing loss, ensure that the headphones or earphones you use
also comply with EN 50332-2 (Clause 7 limits) for a wide band
characteristic voltage of 75 mV. Using headphones that do not comply
with EN 50332-2 can be dangerous due to excessive sound pressure
levels.
If Lenovo Phone came with headphones or earphones in the package, as
a set, the combination of the headphones or earphones and Lenovo
Phone already complies with the specifications of EN 50332-1. If
different headphones or earphones are used, ensure that they comply
with EN 50332-1 (Clause 6.5 Limitation Values). Using headphones that
do not comply with EN 50332-1 can be dangerous due to excessive
sound pressure levels.
Sound Pressure Warning statement
For the device which tests accordance to EN 60950-1: