Fotodiox Turbopack 9000 Power Pack for B4 2/3" Mount Servo Lens Provides power to the Zoom Servo Functions including Quick Zoom, Cruise Zoom & Memory Functions Switchable DC Output to suit your lens needs: 12v, 16v or 19v Battery does not have a sleep function, so the lens will always be ready to go at a moments notice Built-in power indicator lets you know when the battery needs a recharge 24 Month Manufacturer Warranty