ProBax^(R) is the only seat clinically proven to provide optimal long-term back and upper body support. Equipped with a patented base and back dual core foam support system. Water resistant and durable for prolonged use. ProBax^(R) is sewn with UV and abrasion-resistant polyester thread and covered in 30-oz. marine-grade vinyl to stand up to all the elements. Fits most slider systems and any 5-1/4? mounting system when paired with the Elite Mounting Plate. Color Charcoal/Gray/Carbon