GeekBuying.com has Makibes 4000mAh Wireless Power Bank with Magnetic Charging for iPhone7, iPhone6s and iPhone 6 on sale for $16.99.
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Practical 4000Ah backup power bank
High capacity external battery, provides enough power
Ultra thin design, convenient to carry
Easy disassembly, simple and safe
Longer standby time
Input current: 8 pin connector 5V / 2A
Output current: 8 pin connector 5V / 2.4A