Art Bin Super Satchel Scrapbooking Storage Case Rack 15.5 x 16.8 x 15.6 inches The interior walls of each cube are pre-drilled with a series of rows of ports to accommodate a custom designed rail which acts as a support system. The super satchel boxes slide out for easy access to all of your supplies. All Super Satchel Series Boxes are sold separately. Each super satchel cube comes with 6 sets of rails which allows you to store slim, standard, and double deep super satchel boxes. Stackable with other Cubes.