See also:

Tone
Only treble and bass can be set in the rear. The settings are made separately for the left and right headphones. Operation is the same as for the front tone. ...

Navigation bar overview
The functions of the navigation bar symbols can also be stored on the programmable memory buttons ...

Maintenance
The battery is maintenance-free, i.e., the electrolyte will last for the life of the battery. Your service center will be glad to advise you on questions regarding the battery. ...