TARION Battery Back Pack Plate Adapter for Anton Bauer Mount Battery External / for DSLR Camera Video Light Mount Type: Anton Bauer Can power an onboard camera light or broadcast accessory. Material: ABS Flame-retardant plastic and Aluminum Dimensions: Approx. 116X74X11mm/4.5X2.9X0.4'' It is a device which can connect the battery and videoing devices together.