The ultimate bike packing bag by PRO bike gear. This monster 15L seat post bag is sure to provide that much needed storage that you won't have to worry about on your ride. The anti-sway design enables you to focus on your ride without the swaying of an unstable mounted bag.. One large compartment for easy storage . Bungee cord to store quick access items . Reflective strip to mount lights or other accessories and for safety and visibility . Anti-swing construction . Easy Hook and Loop strap attachment . Clip Buckles for seat rail mounting . Low friction surface for bottom of seat protection . Capacity: 15L . Colour: Grey . Manufacturer Waterproof Rating: 5000mm