Gymnastics Super Mat 2' Panel 4'X8'X1-3/8" V-4 Black Cross-linked polyethylene foam 1 3/8" renowned for its shock absorption resiliency and fast response The dense closed cell keeps the foam from bottoming out and the cross-link gives it a softer feel. 18 oz. Knife-coated Vinyl Cover Double-reinforced nylon stitching with inverted seams THIS MAT HAS VELCRO ON ALL 4 SIDES FOR THE ABILITY TO ATTACH MULTIPLE MATS TOGETHER.