The Sony BP-U35 is a high-performance 35Wh lithium-ion battery compatible with select Sony professional video cameras, such as the FS7 (see below). It's designed to communicate status data to the camera, and remaining capacity is displayed on the camera's viewfinder. This battery is rechargeable in approximately 90 minutes using the optional BC-U1A/U2A charger. A 4-LED gauge displays remaining capacity as 20, 40, 60, and 80%.