I purchased this armband for my sister-in-law since she is a runner to hold her iPhone and upon testing, I found it to work well to hold a few sizes of iPhones such as 5s, 5c and 6s. It straps around your arm tightly and with the velcro strap, it allows you to adjust to fit as needed. The only issue I had was how well this will last since the stitching was a bit loose around the velcro strap.
A nice feature is that it does stay secure while running, bouncing, and just being active. I had no issues with it coming loose in the holder as well. As a phone holder for sports, it will do it's job provided it stays together.
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