Accelerator Backpack Boston Red Sox. Hop onto the bus with this Officially licensed MLB Accelerator Backpack by The Northwest Company! Has a front zippered compartment, side mesh pockets, and a large main compartment. Adjustable, padded shoulder straps and back panel. Measures 16H x 5.5L x 12W with 3D raised graphics. 600D Polyester. Spot clean only.