Abstract: The present invention relates to a device holding box flaps open and down along the box side walls, and allowing for secure box stacking. The device has two sides joined at a right angle at a junction. The device has an inside wall with two sections. The device has an outside wall with two sections. The inside and outside walls are joined with a rail, also having two sections. The inside wall is perpendicular to the rail, and the outside wall is divergent from the inside all relative to the rail. The inside wall, outside wall and rail define a cavity that can be slid onto a box to hold two flaps in an open position. A rim with two sections upstands from the rail. The rim is located on the middle of the rail so that a bottom of a stacked box is stacked in a secure manner.