With the Lumsing 11000mAh 5 x USB External Battery Pack, you can charge up to five phones or two tablets simultaneously. The 11000mAh lithium-ion battery holds more than enough power to keep a gear bag full of mobile devices going during your longest trip. The five 5V USB ports output between 0.6A up to 2.1A. The integrated LED power-status indicator shows you how much power the battery pack still holds. It has multiple security protections to guard against overcharge, overvoltage, overcurrent, and short-circuits to safeguard your gear. At 3.70″ X 3.15″ X 1.10″, it will easily fit into your gear bag until you need it. It’s $25.99 and eligible for free Prime shipping at Amazon.