Skillbuilders modular seating system allows for basic Feeder Seat to transform into floor sitter and mobile floor sitter. Each seat has built-in abductor, contoured interior for correct seating posture and a safety harness. Seats are made of molded foam that is firm yet soft to the touch, with integral waterproof coating that is easily washed for years of use. Large seat fits child 49-60" and 50-100 pounds.