The Ortlieb Commuter-Bag Two Urban is a medium sized pannier intended for a bike's rear rack. The Commuter Two uses Ortlieb's QL3.1 attachment system (all the necessary hardware to attach it to a rear rack is included). The interior of the bag is one large compartment with a padded laptop sleeve, two zippered pockets (one approx. postcard sized, the other about double that), a couple pen slots, and an attached lanyard with a clip for keys. The exterior front of the bag also has a small zippered pocket. The bag comes with a shoulder strap and a reinforced handle on the top. As with all Ortlieb products, it's fully waterproof, and the bag closes with a large flap over the front which is secured by a pair of buckles.