The Bottom Is Made Of Environmental Thermoplastic Rubber. Keeps The Rugs/ Mats Long Lasting And More Durable, Strongly Hold Mats Firmly In Place For Safety. This Feature Allows The Bath Mat To Stay In Place Despite Wet Conditions, Thus Providing Protection For Your Family And Increasing Safety Whenever It Is Used.This Is Just What You Need To Protect Your Feet From The Cold Floor And Protect Your Bathroom Floor From Moisture In The Meanwhile, Enjoy Your Shower.