Topeak dynawedge saddle bag the dynawedge is a waterproof saddlebag with a central zip opening to give you easy access to your tools and other essentials the aerodynamic design fits neatly under the saddle and can be secured quickly and easily using velcro fasteners and a rubber seatpost strap featuresaerodynamic and water repellent saddle bagcentral zip opening allows easy access to toolseasily fastened using velcro straps and rubber seatpost strapfits seatposts from 25 4mm to 31 8mmsize 18