Our U.45 is the largest pack in our mavriK™ Series. The U.45 is the largest pack in our mavriK™ Series. In contrast to common clamshell style packs, the U.45 features a U-style zipper which allows the main compartment to be opened completely. Once opened, the side panels lay flat, in line with the main compartment. The interior of the pack is lined with touch fastener and MOLLE webbing for attaching pouches and accessories.