Shell Desk Chair offers intuitive adjustments and a sleek design that fits into any space. Contoured plastic back delivers lumbar support. Seat naturally flexes to fit you comfortably and adjusts in height from 17" to 20". Black vinyl on the seat and arms provides another layer of comfort. The vinyl is also easy to clean. Holes in the back allow breathability. Casters on sturdy, five-star nylon base and 360-degree swivel capabilities make mobility easy.