As discussed in the criteria for the evaluation section, most of the running armbands available in the market today are adjustable. However, there are still few that are not. Adjustable bands often come with a Velcro strap that provides adjustments. You can easily fit it in your running armbands by tightening or loosening the belt. Most of the products in this buying guide are adjustable. Some are available in various sizes for a better fit.