All Party-Pad mats are constructed out of premium grade cross linked closed cell ultra high buoyancy XPE foam, it is a safer alternative to EVA and PVC. It is free from phthalates, BPA, latex and formaldehyde (that's what causes that toxic smell when you open other water mats!) It's also hypoallergenic, anti-microbial, odorless, noise and shock-absorbing and ultra cushioned.