Plantronics Calisto 620 Spare Battery - For Speakerphone - Battery Rechargeable - 930 mAh - 3.7 V DC

Resists overcharging and electrolyte leakage Delivers 3.7 V DC to your compatible speakerphone, ensuring that your device is ready to use when needed Provides reliable power to your speakerphone with a capacity of 930 mAh Rechargeable battery - Lasts longer on a single charge than its disposable counterparts