This vandal-proof swing seat features galvanized welded triangular hardware that makes it one of the sturdiest swing seats available. The dimensions of the seat are 24in x 6in x 5/16in or 30 1/4in hanger to hanger. It is made with 70 EPDM rubber with insert to resist vandalism. EPDM: Ethylene-propylene-diene-monomer is a synthetic rubber material which helps prevent crazing, cracking and oxidizing. Natural rubber is often made from recycled tires etc, and you are never sure what the actual rubber.