This is the perfect bag for the longer days in the saddle when you don't want to weigh your jersey down with extra bars/ gels/ camera/ phone/ gloves/ etc., or the days when you don't want to wear a jersey at all. You can fit a surprising amount of gear in this small bag- pretty easily squeeze 2 bars, gels, gloves, phone, and a small multi tool. Doesn't bounce around much on the bars, and doesn't take up much room either. I do wish it had a small external mesh pocket(s) for things like bar wrappers/ spent gels etc. because you'll end up with crumbs all over your phone/ wallet post ride. Although a bit pricier than similar options, I definitely recommend.
Great size for tube, tools and snacks