The Ortlieb Seatpost Bag – Medium is a versatile and lightweight saddlebag. Ideally suited for day tours by road or mountain bike. Lightweight with an integrated mount. Ortlieb have designed this to be removed or fixed in one simple, tool free manoeuvre. Its integrated mounting allows fast changes between your bikes. The waterproof Ortlieb Seatpost bag is made from PU coated nylon and Cordura for an abrasion resistance.