I just bought a pair of axiom randonnee aero 40's. They have an external pocket with a waterproof zipper. All the seems are sonically welded. They seem rain proof although they don't close water tight the way ortlieb classics do. Rather they have a draw string at the top that is then covered by a cover flap that buckles to the base of the bag. The flap has elastic so it stays tight around the bag. No back pack straps though. Just a single shoulder strap. I commute in Florida so ill find out how rain proof they are. Just got them last week.