The present invention is a system for attaching rigid holders together to form stacks of rigid holders. The present invention relates particularly to stacks of one or more rigid holders for containers holding compact discs and DVDs. The attachment system of the present invention allows for simple and efficient connection between individual rigid holders. Mechanical binding clips are inserted into cutouts on the spine region of rigid holders. The binding clips are flexed to fit within an opening and then un-flexed to lock the rigid holders and binding clips together. Male and female details allow for a secure hold. Extensions within the cutouts have barbs that fit over parts of the binding clips.