Features a rear storage pocket for an optional 1L Reversible Reservoir II Water Bladder Drink System * Constructed of 210D Baby Rip Nylon, 420D HD Nylon, Hypalon, and a 840D Nylon Bottom Panel * TRAMP Vaulted Suspsension back panel system features Ultra Mesh and Corrugate Foam Pods * Dedicated laptop pocket will accommodate up to a 15" laptop * Ultra durable Pro Air Mesh Padding on back panel and straps