What is "poly-turf"

Poly-Turf was a brand of artificial turf, manufactured by American Biltrite of Wellesley, Massachusetts. It was the first specifically designed for American football, with a patented layered structure which included a "shock pad" between the artificial grass and the asphalt sub-surface. It used polypropylene for its artificial grass blades, rather than the nylon used in AstroTurf and 3M's Tartan Turf.