Limefuel, makers of the Limeade backup battery pack, have gone Rugged. As its name would suggest, the 15,000mAh L150XR Rugged has the highest Ingress Protection rating in the external battery market (IP66), and calls itself not just resistant to infiltrating outdoor elements, but entirely dust-, water-, shock-, crush-, and vibration-proof. Limefuel's video demonstrates some of these attacks in action, and the Rugged's response to them.
The L150XR has a 5V/2A(max) input for faster charging, plus dual 5V/2.4A(max) outputs for charging multiple devices at once. Additional features include a touch-sensitive power indicator, pass-through charging capability, and auto-on/auto-off functionality.
Rugged is also available in a smaller, the L104XR 10,400mAh model. It too is up for hanging in your wood shop and getting run over by your SUV.
Rugged external batteries are stalwart companions for emergency and industrial workers, adrenaline junkies, urban adventurers, and travelers who would be SOL without a GPS or smartphone, and supremely pissed off if their GoPro went dead right before they landed a huge jump.