It's perfect for running/exercising and rarely slips off your hips. I think it stretches a bit with constant use so I might have to scale down next time. For reference I ordered L, I'm 5ft 3in and about 145lbs. I have wide hips and wanted to sit comfortably on my hips. If you sweat a lot this strap is not fully waterproof but it does keep the contents dry for most of my workouts/runs.