The side walls come with full-width velcro across the top edge that allows for a tight, smooth seal with the valance of the canopy. They also have fully zippered ends for mating to other sidewalls, and each have velcro tabs for attaching the wall to the legs of the canopy for maximum strength. All sidewalls zip together at their ends.
When the canopy is set in the third highest position the lower edge of the wall is at ground level, thereby keeping wind and rain from the canopy.
With the canopy legs extended to the highest position, the lower edge of the walls hang approximately 4 inches from the ground. This allows for airflow under the canopy, and keeps the sidewalls from being damaged by being dragged on the ground.