Agree with Maccy, Anker make good kit and its the best one Ive had.

Get one thats at least 5000mah, that'll do an iphone to full charge 2 or maybe 3 times.

Ive made the mistake of buying tat off ebay and regretted it. Buy a decent one 5000mah or even 10000mah+ if you're a heavy user and wont see a charge point for a while.