Galvanized triangular hardware makes this one of our sturdiest swing seats. It is made with 70 EPDM rubber with insert to resist vandalism. EPDM: Ethylene-propylene-diene-monomer which is a synthetic rubber material which helps prevent crazing, cracking and oxidizing. It measures 6" x 24" x 5/16" thick. The seats insert has bent edges to prevent injuries from sharp edges and then encased in EPDM rubber. The seat should last 2 years in harsh conditions and up to 5 years in optimal conditions. Some conditions may require replacement sooner.