Already bought this bag while waiting for the iron. Brought it home yesterday and it is marvelous. The base will fit over either the standard of the plush seat. It is actually quite large and seems well built. There is a large zipper and a flap that folds over the zipper to keep your things dry. A couple of straps hold it in place and is easily mounted or removed from the bike. There are pockets on both ends (like the one seen above on the left side). They, too, have a weather resistant fold over flap. Now, when Nancy needs something from the store I'll jump right up and be on the road in a flash. The bag is large enough to fit quite a bit of groceries in it, has a sturdy bottom to keep things upright, and will keep enough clothes for a weekend trip to see my son. I had thought about getting the tank bag too but now see that it won't be needed even for weekend trips. This bike is not a cross country tourer, though our ancestors rode lesser bikes around the world and this could too. But if I had wanted to do that I would have bought the GSAdventure - which I saw the 2014 model yesterday and almost bought it too.