With high density foam material, the 1/2'' thick premium mat comfortably cushions spine, hips, knees and elbows on hard floors. Easy to clean. The moisture resistant technology and high quality material make mat to be easily washed with soap and water. The mats are made of high density EVA foam material. They will last long. Sturdy enough while giving you necessary cushion. With high quality material and precise cut, the puzzle locking system locks mats together tightly so they won't come apart easily. Mats are designed with the non-slip pattern surface on one side and flat surface on another side. The flat side faces floor. 3 colors to choose from: Black, Gray and Blue. Each pack comes with 36 tiles and 72 end borders, 144 square feet covering area total.