Add-a-mat velcro ends allow mats to safely connect to other mat to "expand" and form a larger mat surface. CanDo accordion fold mats are durable enough for the school, gym and clinic setting. The accordion fold mats fold every 2 feet to minimize storage space when not in use. The 1-3/8" thick EnviroSafe foam mats are covered with 18 oz. tough fire-retardant phthalate-free PVC coated vinyl; cover is sewn around foam. The vinyl coated nylon cover is strong, mildew resistant, anti-bacterial and wipes clean with a damp cloth. The mat is made with square side walls and is reinforced at all stress points for added durability. 1-3/8" thick EnviroSafe foam has an extra-firm firmness. The EnviroSafe foam mats are eco-friendly. They are 100% toxin free, zero VOC's or off gas, hypoallergenic, latex-free, mold and mildew proof; 100% recyclable with no leaching chemicals. Various sizes and colors available.