See also:

Replacing the battery
- Do not let dust, oil or water get on or in the transmitter when replacing the battery. - Be careful not to damage the printed circuit board in the transmitter when replacing the battery ...

Adjustable level of each volume
...

Certification for the Handsfree system
FCC WARNING Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. NOTE This device complies with Part ...