Be aware it likely won't work for a more bulky case

My Samsung Galaxy S7edge WITH a protective case still fits into this armband nicely and it fastens securely.

I can fit my gym key fob in the key pocket, and it fits my S7 with a case well.

It is a little snug with my phone's protective case on, but works very well with a 'naked' phone.

It is a good case if you have upper arms under 12" in circumference, with the exception of like some people say, the plastic window does stick to the phone screen and makes it a pain to get your phone out of the band when you are done.