Sennheiser BA 20 Rechargeable Battery Pack

Rather than having to purchase a separate charger, the BA 20 Recharging Battery Pack features a USB charging port, directly on the unit. To recharge the BA 20 Battery Pack, a separately available USB 3.0 Male Cable, can be connected to a PC, or wall outlet (with an additional AC Adapter). The separately available USB 3.0 Male Cable, helps to cut costs, due to a significant decrease in price, as opposed to having to purchase a separate charging unit.

Specs

Charging Capability: 430 mAh
Output Voltage: 3.7 V