These seats will help make your playground safe. Galvanized welded triangular hardware makes this one of our sturdiest swing seats. It is made with 70 EPDM rubber with insert to help prevent 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.