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. Floor sitter set includes seat and floor sitter wedge. Seat is secured to the wedge with velcro and can be adjusted from upright to reclining position. Medium seat fits child 37-48" and 30-60 pounds.