Announced alongside the a9 is an accessory that should excite existing E-mount camera owners, particularly videographers: the NPA-MQZ1K Multi-Battery Adaptor Kit. It comes with two of the new NP-FZ100 batteries and has space for another two. The kit not only works as a charging station for up to four Z type batteries, but also has a dummy battery that allows it to be used as an external power pack.

The unit is compatible not only with the a9 but also with the a7, a7R, a7S, a7 II, a7R II, a7S II, a6000, a6300, a6500, a5000, a5100 and RX10 III, providing up to 8x their current battery capacity. It includes tripod-style mounting sockets for attachment to a video rig.

The dummy battery is the same shape as the a9's new 'Z type' battery but has an outer shell that can be removed, revealing a 'W type' adapter, which can slot into cameras that use the NP-FW50 battery.

The unit, including two batteries, has an MSRP of $399.