Ortlieb have a new bicycle touring luggage system on the market. The Seat-Pack is one part of the four piece bikebacking kit (the other components include a handlebar-pack, an accessory-pack, and a frame-back). Designed as a single waterproof saddle bag with a roll top closure system, the new Seat-Pack has a carry volume that adjusts between 8 L (488 cu.in.) and 16.5 L (1007 cu.in.) and is attached to your bike’s seat post and saddle rails. An additional benefit is the blocking of wheel spray like a mudguard. Weighs only 430g (15.2 oz).