The Vaude Silkroad M is a bike bag that lies on top of your bike rear rack, so it's very stable. The bag attaches to your rear rack with velcro. There's a zipper compartment on top for storing smaller things. There's rack straps that you can strap things such as a (rain)coat under. A removable shoulder strap ensures that you can easily take the bag with you, once you leave the bike and continue on foot.