both free ends of the duct abut the same end wall in the manner depicted in fig3 when the duct is in simple axial orientation the opposite ends of the duct will abut opposite ends of the carton such a duct is considerably compressed axially in this packed condition such that by closure of the flaps to form the end walls there is resilient bias against the end walls by the duct in one of the smaller side walls is a breakout panel 12e this breakout panel is defined in the carton blank adjacent one end of the wall in which it is formed the side edges 12f of the breakout panel are spaced an amount equal to the width of that particular side wall i e the depth of the carton each side edge having a series of perforations along each of the two parallel side edges thus the distance between these perforated lines is at least about equal to the diameter of the duct and preferably slightly larger the base line of the breakout panel comprises a score line 12g transverse and preferably normal to perforated lines 12f and parallel to the bend or score line 12h between this breakout panel and the end flap 12i integrally attached thereto this flap 12i also includes a finger grip.