This swing seat is made of heavy duty polypropylene. The seats are made wider and sturdier to hold both small and large children that may use swings on the playground. The Roto Molded Flat Swing Seat meets ASTM standards for safe commercial use. The seat is available in black, blue, and green. The seat dimensions are as follows: 20″ long by 9-1/2″ wide at the widest section of the seat, 2″ thick, 16″ between hangers.