I just recently received a nice little charging power block from my bank as a gift (as well as some teriyaki flavored reindeer sausage). The power block is about half the size of a cigar, but squared off on the egdes and it'll fit in my pocket. When it's fully charged, it'll bring my iPhone 7Plus from 60% charge up to 100% charge. I try to keep it fully charged and then when I'm watching TV I'll hook it up to my iPhone to charge it so I can still keep my phone right next to me and not have to have it hooked up to a wall outlet charger.