These gym crash mats consist of a sponge foam core with heavy duty 18oz. vinyl top and mesh sides (purple crash pads have vinyl sides). Convenient handles on the sides allow for easy handling. These premier gym crash pads provide maximum shock absorption to keep your gymnast or cheerleader safe while practicing routines. Our 4' x 6' or 4' x 8' bi-fold gymnastics crash mats fold in half for easy storage.