Altura: ESSENTIAL TO ANY BIKE PACKING ADVENTURE, OUR WATERPROOF SEAT PACK RANGE HAS WELCOME UPDATES INCLUDING IMPROVED STABILITY AND CUSHIONING  The Altura Vortex Large Cycling Seat pack is a fully waterproof essential for multi-day adventures with improved stability from the previous model, added cushioning and glove compatible buckles which allow you to access your belongings quickly and conveniently when needed.Engineered from Polyamide Ripstop with TPU coating it is fully waterproof with welded seam construction and comes in three generous size options giving you the choice between 17, 12 or 6 litre capacities.The 17 and 12 litre versions include a handy bungee cord for extra storage and they are also compatible with the Altura Anywhere Dry bag range.The roll closure allows you to adjust the volume of the seat pack to fit the contents whilst the reinforced inner prevents them from becoming crushed against the seat post. Reflective details and light attachment loops help to keep you visible in lower light conditions making it ideal for any adventure.  FEATURESWaterproof, welded seam construction Polyamide ripstop fabric with TPU coating Bungee cord for extra storage (regular and large only) Compatible with Altura Anywhere drybags Adjustable volume via roll closureReinforced inner to prevent crushing against the seat postReflective detail Light attachment points Air release valve