The Altura Vortex 2 Waterproof Large Seatpack is the largest seatpack Altura make with a whopping 17 litre capacity. It is also fully waterproof so it is perfect for bike packing adventures. The positioning of the Vortext Seatpack helps you stay aero & efficient on your next bikepacking trip. It also means the bag works better with full suspension bikes. The durable welded seam construction makes the bag fully waterproof & durable. It comes complete with the hook & loop mounting system that ensures reliable secure fastening to the saddle rails. The clever roll closure ensures the pack can be effectively used for lighter loads. While compression straps help achieve a streamlined mounting that wont impede your speed. Complete with reflective details so you can be spotted in low light. Features Waterproof design roll closure hook & loop mounting system elasticated cord system reflective details up to 17l capacity