A topper unit is disclosed which may be utilized for opening, applying and locking a pre-glued open ended carton to the top of a bottle which is being progressively moved through the machine employing the topper unit. The topper unit may be used either singly, doubly, or in greater multiples in a packaging machine and comprises a hopper for receiving the pre-glued and folded cartons. Located below the hopper are means for removing the cartons one at a time from the hopper while opening the cartons so that they can later be applied to the top of the bottle. When the cartons have been opened one at a time, they are then pressed onto the bottle while they are squared up and are then ultimately locked onto the bottle. Also disclosed is a new and novel method for withdrawing a pre-glued open ended folded carton from a hopper and opening the carton and applying it to the top of a bottle or a plurality of moving bottles.