Its a P charging board...
On ebay they say it takes the original DJI power adapter but from what I see mine does not have round plug so I am not sure what they mean...?
Yes I see what you mean also after some research h it looks like there is no benefit as the one charger any gives out enough power to charge one battery so plugging two in would take longer to charge. The suggestion is to spend £30 on extra charger.