The sides are connected to a panel that swings in and adds an extra layer to the bottom of the box.
Lock into both sides on the front of the box.
The sides of the box have a second layer of material folded over for extra strength
How deep the dust flap goes into the box depends on the size and location of the roll end side tabs.
When the height (or depth) of your box is more than half the width (H>0.5×W), the dieline of this box is more compact and wastes less material than a standard Roll End Tuck Front (RETF) with the same dimensions.
The Economy Tuck Top only requires a strip of tape or a label to keep the lid closed in shipping.