This power bank from Poweradd is a good compromise between portability and charge capacity. It's a 20000mAh power bank which measures 16.2 x 6.3 x 2.4 cms and weighs 365g so can easily be carried in a pocket, handbag, backpack etc. This charger has 2 x USB outputs meaning that you can charge 2 devices at the same time which is very handy if you carry a tablet around with you as well as a phone.
This power bank comes in a box along with a user manual, storage pouch and a USB to micro USB cable. To see this Poweradd EnergyCell power bank on Amazon use this link: