Abstract: An extruded plastic tray has along the upper side of its rear portion a forwardly opening "C"-shape channel into which "C"-shape clips slideably engage by bowing the bights of the clips so that the arms of the "C"-shape clips can pass between the arms of the "C"-shape channel on the tray. In the bights of the clips are "I"-shape slots through which the ends of divider strips may be forced so as to bend back the side edges of the stem of the "I".