The big changes to Gum Max Duo can be summed up simply: start with late 2011’s silver aluminum and black plastic 10,400mAh model with 2.1-Amp power, which measured 4.3” by 3.2” by 1.1”. Replace the battery with a 11,200mAh version, and up the rated output speed to 2.4 Amps, which is supposedly enough to refuel even Retina iPads at their peak speeds, as well as supporting the top recharge speeds of all other recent iPad, iPhone,…
