This is a really nice, high quality, top tube bag.
The straps are nice and large so that when you secure it, it sits firmly on the bike. You can also, easily, take it on and off the bike because of the nice Velcro straps. If you ever have a cheap bag you'll know why good quality is important.
The bag itself can fit a few items as one would expect.
If you leave the bag unzipped the bag stays fairly well closed, so that even though it's not as secure as being zipped shut, you don't necessarily have to worry about things just bouncing out.
I purchased this to store my essentials during the Dirty Kanza 200 and Michigan Coast 2 Coast and I'm very satisfied with how the bag held up. I expect that I will have this bag for a long time.
Nice pack for getting your phone, extra bars, etc off your back. Generally fits, a cell phone, two Clif bars, small tube of sunblock (and a little room for keys). Secures snug to the frame with velco, slips under cables well too.