For shorter activities, I use my smartphone instead of a full-blown GPS device. With the on-board GPS module and a constantly running Map and navigation software Of course, the battery of the smartphone will last only a few hours.
The iPhone Case by Dura Case allows with the 4500 mAh battery about 3x longer continuous operation in navigation mode, is also waterproof up to three meters and fall protected up to three meters. Thus Dura Case is for me the perfect smartphone case for longer day trips and Overnighter. In flight mode, only occasionally on the mobile phone network and briefly to get the GPS signal, the battery of the smartphone now holds several days.
The case is clean and stable processed: a lever opens a flap, the smartphone slides into the shell and closes the flap again. Finished. All functions or all switches of the iPhone can be accessed and operated from the outside of the case, and even Touch-ID works without any problems. Of course, the case is much clunkier and heavier than the smartphone alone. But you also have to accommodate the 240% power.
Only the volume of phone calls is muted by the case. For this you should use a Bluetooth headset. If you use a normal headset with a cable connection, a flap must be opened to get to the port - this makes the case of course no longer waterproof.
Through this flap you can also reach the socket for charging the case, as well as another button to push the iPhone slightly upwards and take it out of the case.
On the back of the Dura Case is a single large and flat push button, with which you can, briefly pressed, using the built-in LEDs query how much power in the case is still present. Long pressed, starts or stops the charging of the smartphone.
An intelligent technology switches off the network charging process of the case itself. Even when the iPhone is fully charged, the case turns off automatically. It would be nice to have another circuit here: if the case is switched off, and the smartphone falls below, let's say 20% battery charge, the charging process could automatically turn on again. At the moment you have to start the charging process by hand.
Other accessories for every adventurous application can be ordered separately: various brackets and mounts, for example for the rucksack or for the bicycle, floats and safety line and even pulse, cadence, or speed sensors.