1. TRIANIUM ATOMIC BATTERY CASE FOR IPHONE 6 ($60)
This is a top seller on Amazon, where it averages 4.5 stars. The 3,100 mAh battery can completely recharge the 4.7-inch iPhone 6 (and then some). Put another way, it delivers an extra 10-plus hours of web surfing. The protective design has a very slim profile and a hard-shell back with indicator lights to show how much power remains.