The Ortlieb Back Roller Plus QL2.1 is both a commuting and touring favourite. The Back Roller Plus uses a lighter-weight Cordura finish, fully backed by a laminate, which is more eco friendly and expensive than the heavier, arguably tougher PVC versions. The design of the bag is really simple and the name of the bag is based around how the bag closes shut. They roll up, with a single clip and strap holding them shut. It's basic, but it works very well, the roll prevents water from getting through while allowing enough slack to accomodate larger loads.