The exposure support cell is an additional add on power supply that comes in a robust carbon fibre shell for lightweight durability it is simply connected to any light through the smart port to extend burn times or can be combined with the boost cable to charge usb devices some apple products are incompatible the support cells are available in 17amphour 29amp hour and 87amp hour options and are supplied with mounting blocks and a 30cm cable 80cm for 87a that can be easily mounted or s