What's a good backup battery for my mobile phone?

Episode 1179 (1:40:22)

Todd from Topeka, KS
Aukey external battery

Todd is going to be travelling to the Grand Canyon and he's not sure what kind of reception he'll be getting. Leo says the Canyon isn't ideal for cellphone coverage. Will it work OK with power? Leo says he can get huge backup battery to charge it back up. A 10,000 mAh battery would be able to recharge three times before needing to be recharged. Anker makes a great one. Aukey makes one that also does quick charging for $35 at Amazon.