I have a commuter bike with a rack and panniers and wanted a bag to use to commute with my unracked bikes. This one does the trick pretty near perfectly. First, it holds plenty; I pack an old seat pack with tube and tools, fresh underclothing and towel (suits at work), and a lunch. Plenty more room. You can not carry a laptop or even a full tablet, but it has plenty of space for gear. The straps and connections give a secure carry, however, there should be a better guide or youtube to show how to store the strap ends--and there are plenty if you have a small load. The saddle post mounts are secure and nice, but I am unaware of how to quickly release them if you want to take the seat pack off to take with you. I resort to unpacking the bag which is not too handy. The bag rolls closed; do it so it does not trap water. Very nice commuter bag or probably touring bag if you have big handlebar bag and frame bag. It does not claim to be waterproof, but I have used it in showers without problems.
