You would probably find it a lot more comfortable to use a belt instead of an armband. Personally, I think the Nexus 5x is too big to run comfortably with it on your arm.
I actually tried this one for use at the gym (pretty generic and similar to other designs) - cannot post links. It was OK at the gym but would not be good for running. Here is my review from Amazon...
For the price it seems to be made really well. It fits the Nexus 5x perfectly, I do not have a case on mine but it should not be a problem with a thinner type case. I kept my gym membership card behind the phone in the same pocket. The headphone port lines up correctly with the cut out in the armband, although I use Bluetooth headphones. I was able to control the screen over the “plastic”, front panel although it is never easy to do when it is on your arm.
Now for the downsides. I measured my bicep and it is around 14.5” inches. With the phone I can barely get the strap to work, it is too short. I could not attach the strap at its widest point, then slide it up my arm and finally make a tighter closure. Instead I had to strap it through the outer slit while holding it in place against my arm, not the easiest thing to do. Also, the strap does not have any stretch to it so you have to make sure you have it tight enough to stay in place but not too tight to be uncomfortable.
Since the fit is too tough for me, I’m giving it 3 stars. The description says it will fit up to a 17.5 inch arm, but there is no way that is possible with the phone in there. However, if you have smaller arms (I promise mine are not big), then I would probably recommend this armband given the quality and price.
LG Nexus 5X Armband Case for Running Workout Exercise Housework Sports Activity by Noot
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