THIS used to be my choice for carrying tools and other close-at-hand necessities on trips.
There are however a couple of problems with the bag as a touring item. Firstly it needs to hang as vertically as possible to stop stuff falling out and so is better suited to bikes with slanting top tubes which have a higher seat post. It also isn't too compatible with a rear carrier and panniers which tend to push it into a more horizontal postition. Mine has also worn a hole in itself rubbing against the seatpost bolt.
