The Fitly 8.5oz Soft Flask is the perfect handheld for short or long runs. Helps me get through runs anywhere from 5K-10mile on a single fill. The 8.5oz fits perfect in my hand, no leaks, shrinks as I drink, and if I finish it off on the finishing mile I can roll it up in my hand or put it in my pocket with no issues. I have been running with these flasks (5oz/8.5oz) for almost a year now and wouldn’t reach for anything else.