Packing list: 1500mAh battery pack x1. Compatible with beyerdynamic Lagoon ANC Traveller Bluetooth Headphones. Specifications: Battery Type: Polymer Lithium Ion Rechargeable Battery. Battery Capacity: 1500mAh. Rated voltage: 3.7V. Fully charged 4.2V. Power:5.55Wh. Shutdown voltage:2.85V.