The Ortlieb Seat Pack Medium is a spacious and waterproof Saddle-Bag with roll closure; its volume is a spacious 11 litres. An additional purge valve allows air to escape making tight packing easy. The Seat-Pack securely fastens to the seat post and saddle rails of almost any bike. Robust fabrics, custom stiffeners and an optimized strap design ensure the Seat-Pack performs in harsh off-road conditions and safely transports your gear. At only 430g it is super lightweight. Ortlieb Seat Pack Medium Features Elastic cords Reinforced fabric at contact points to saddle Saddle-Bag blocks spray from the rear wheel like a mudguard Reflectors Loops for tail light Height - 30cm Width - 64cm Depth - 22cm