This review is from: Anker PowerCore+ mini (3350mAh Premium Aluminum Portable Charger) Lipstick-Sized External Battery Power Bank for iPhone 6 / 6 Plus, iPad Air 2 / mini 3, Galaxy S6 / S6 Edge and More (Black) (Electronics)
Not much bigger than the average lipstick, great to chuck in a bag and have the peace of mind for an extra 1.5 charges for the iphone. Highly recommended! Some advice, batteries take a lot of oomph to charge from 80-100%. Using this wisely if on the road (charging from 20 up to 50%) the battery can literally keep you powered for days...