Nucleus Series Work Chair, Ilira-stretch M4 Back, Supports 300 Lb, 17" To 21.5" Seat Height, Espresso Seat, Black Back-baseSlender, contemporary look coordinates well with most open plan systems. Unique materials and innovative construction deliver surprising comfort without bulky padding. Multi directional stretch mesh back puts lumbar support right where you need it. Internal structure of seat uses unique stretch material that eliminates pressure points. Height and width adjustable arms for custom comfort. Five star base with casters for easy mobility.