The Vario PS from Ortlieb is a unique 26 liter bag that transforms from backpack to pannier in seconds. Purpose built for those seeking the versatility of a backpack while off the bike, but the convenience of a pannier while riding. The Vario PS is durable and waterproof, featuring an interior laptop sleeve along with zippered pockets inside and out for small items. This one comes with their Quick-Lock QL 2.1 latching mechanism for attaching to a bike rack.