First, I’m not a runner but an avid walker. I had a NB armband case I had to cut a bunch of neoprene out of just to fit my iPhone 13 Pro Max with a modest clear case. This armband has plenty of room for my phone and I’m sure it would fit in if I had an Otter Box case on it without issue. The band and the Velcro on the NB broke down less than 6 months of use. This armband has actual elastic band with the Velcro secured quite well. I purchased the large case which came with the extender strap, but there’s no need for that. The standard band is bordering on too long for my bicep which is about 13” in circumference. That said, I could see it potentially slipping down my arm if I were a runner. I still use wired headphones and openings on the bottom allows for access to the lightening port. I am wondering if the smaller one would still fit my phone and if the armband would be a little tighter. If it’s off my arm, facial recognition works when I hold the clear plastic against the phone, otherwise touch works to enter my PIN. It gets warm and I tend to sweat probably more than others, but the phone stays dry. I haven’t used any of the accessory openings for keys or cards.2/19/24 update: I added jogging into my workout routine mid-summer 2023 and these cases are invaluable. I have used the key pocket since the original post but only put a single key in it. I have also used the card/money pocket as well where I’ve gone on a jog and planned to stop at the pharmacy to pick up a prescription. They are both handy options. I purchased two more over the 2023 Christmas holiday and gave one to my sister. One of them I purchased was the smaller model. The one still in its packaging is the new smaller one. You can see the difference in the size in the photos. I do find that when I am jogging the larger one will tend to slip down depending on the arm it is on, so that was the reason for purchasing the smaller model.