How cool would it be to pack your stuff in a bag that clips onto your bike, then converts into a backpack when you're walking around, and when it's time to go home clips right back onto you bike? That's what Ortlieb has achieved with their Carrying System for bike panniers (sold separately). The pannier clips onto the mounting points and then you're on your way. A foam back improves air flow and comfort, two shoulder straps and a chest strap supports the weight, and there's even a carry handle if you want it. When you're ready for the bag to go back on the bike simply remove the Carrying System, roll it up, and slip it in the bag, and you're off!