One piece white molded shell. LLDPE Plastic with UV inhibitors for years of carefree use. Cushions are made from plush foam padding covered with marine grade vinyl. Heat seal channel designs, quick dry construction, snaps easily to the seat. Includes mounting plate that adapts a swivel mount to fit most seat mount patterns. High strength aluminum. Seat dimensions: Height 19-1/2″, width 25″, depth 17″.