Each Super Satchel Cub comes with 6 sets of rails which allows you to store Slim Standard and Double Deep Super Satchel boxes. The interior walls of each Super Satchel Cube are pre-drilled with a series of rows of ports to accommodate custom designed rails which act as a support system. The Super Satchel boxes slide out for easy access to all of your supplies. Assembly required. Stackable. Holds up to 6 of the Slim Super satchels or 4 of the Regular Super satchels (NOT INCLUDED).