Double Organizer Pouches add two extra pockets of organization to any bag. Front pocket is clear, and the back pocket is concealed. Using a small-but-tough plastic snaphook, Double Organizer Pouches attach to any of the O-rings inside our messenger bags, backpacks, briefcases, travel bags, laptop bags, and knitting bags. If you have another bag, that's ok — just don't use the little plastic snaphook on the pouch or break it off. Double Organizer Pouches zip with a #5 YKK coil zipper with a plastic slider, which is less likely to damage sensitive electronic gizmos. DIMENSIONSSmall: 7.1" (w) x 5.1" (h) / 180 (w) x 130 (h) mmMedium: 10.2" (w) x 7.1" (h) / 260 (w) x 180 (h) mm The clear material used on the front of the Double Organizer Pouch is made of urethane instead of PVC. This is a conscious and, we hope, conscientious decision on our part; PVC is pretty nasty stuff. It isn’t good for your health (ever open a brand-new PVC shower curtain, get a headache, and wonder why?) or the environment. The European Union has gone so far as to ban PVC children’s toys. Unfortunately, PVC is still the third most widely used thermoplastic polymer, in part because urethane and other alternatives tend to be more expensive than PVC. We think the added expense of urethane is worth it for the health of you, us, and the planet.