Developed for military use, this is the beach mat that is impossible to cover with sand. The 64' mat is made from two layers of woven polyurethane that instantly filter sand to the beach as soon as it falls on its surface. The polyurethane acts as a one-way filter, preventing sand from reemerging through the bottom of the mat. It also eliminates dirt, dust, and water from its surface, is rip proof and won't absorb moisture so no mould. Genius.