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.
Keep dust from entering the box, and adds padding along the sides.
There is no glue or tape required to assemble an RETF, just a strip of tape or a label keep the lid closed in shipping. Dust flaps and cherry locks protect from debris, and the roll over sides add stacking strength and padding.
This is the most popular box style for ecommerce brands, because of its ease of assembly, and prominent surfaces for branding and messaging.