Troubleshooting for Nokia Purity Pro Wireless Stereo Headset by Monster.

With a wireless connection, the fully charged battery has power for up to 10 hours of talk time or 24 hours music playing time, or up to 7 days of standby time.

With wired connection, the headset does not use battery for the connection connection at all, so you can use it even if the battery was empty. However, some features, such as Active Noise Cancellation (ANC) may not be available until you recharge the battery.