Briggs & Riley Verb Advance Backpack, Black, One Size 400D lightweight nylon twill fabric resists moisture, wear, dirt and abrasion Top u-shaped opening offers quick and easy access to main compartment Durable carry handle provides a comfortable grip Adjustable padded backpack straps; Capacity: 21.8 L Aerated mesh back padding allows air to circulate against body, keeping back cool and providing lumbar support