I don't know, it doesn't even clearly say how much energy it can hold...How many times can this battery pack fully charge the surface pro 3?
I imagine it can deliver 20000mAh at 5V, so it might have 100.000 mWh. Considering the SP3 has a 44.000 mWh battery, it should be easily more than 1 time.
TBH, I would not trust some battery where they don't even advertise the capacity...