The Yoga Studio Sticky 4.5mm Yoga Mats are made To European Standards. They are made from the latest environmental polymer resins. They are 6-P Free, Free of Phthalate, AZO, DOP, Phenol, Heavy Metals. i.e. No Nasties at all. Simply - these are the Best PVC mats you can buy in Europe - which surpass European quality standards. This quality yoga mat is the choice of many yoga teachers and yoga students.