Polyester.
6-inches and an expandable 1-inch side for added storage space.Solo Classic Expandable Messenger Bag - Black The Solo classic expandable messenger bag showcases a padded compartment that will protect a laptop up to 15.. It features a front zip-down organizer section, a padded carry handle, a Rear Ride Along(R) strap for consolidated travel, and an adjustable shoulder strap with a speed buckle closure.