Concept 101 External Battery Pack with 3000 mAh Capacity for iPhone, Android, Smartphones - Retail Packaging - Silver

UPDATE:I’ve had this wallet size portable power bank for about 6 months now. Upgrading to 5-star because the “quirk” doesn’t seem so bad anymore. Thickness is about the size of four stacked quarters. I actually carry it in my wallet. Added pictures for size perspective.I like that there is a micro USB and also lightning output pigtails built in sonyou don’t have to carry the charge cables. The pigtails could be a bit longer though. One quirky behavior is that after plugging a device to charge, you have to press the button before it starts charging. I guess that’s okay so long as people know/remember to do that. I also did a capacity test and it’s on par with the rated capacity.