The Bowens Travel-Pak Battery is able to power two Bowens Gemini monolights simultaneously, with a total power of up to 1500 watt/seconds. It is capable of recycling one 500 watt/second unit to full charge in 4.5 seconds, and can offer one unit over 200 full-power flashes on a single charge.
This unit is still in its original box and unused - like new.
I've been advised £300 as its unused and in excellent condition. However, feel free to make me a reasonable offer. I also have a Bowwns Gemini espirit 500 kit and asking £485 for that. Cheaper if you buy both.