Black Friday 4-cell, up to 8.5 hours Battery, Continuous music playback time: Max. 30 hours(NC ON), Max. 40 hours(NC OFF) Continuous communication time: Max. 24 hours(NC ON), Max. 28 hours(NC OFF) Battery, Continuous music playback time: Max. 30 hours(NC ON), Max. 40 hours(NC OFF)Continuous communication time: Max. 24 hours(NC ON), Max. 28 hours(NC OFF) Battery