Not sure. There are a variety of products that have been and continue to be developed. Most are plastic, rubberized webbed products. Some come in rolls, some cut to square with different stall sizes. In addition to the cushion effect, they will provide more of a uniform sloped or flat floor when placed on top of clay or other stall bases as compared to clay alone. Most of these products are made to be removed/lifted when redoing floors, spreading lime or other substances. You will probably find these products are regionally distributed, so look online and in horse magazine ads.