Our height-adjustable desk chair will grow with your little one(6-15 years old). The premium gas lift system and an adjustment lever allow the chair to easily lift up and down. Ergonomic backrest helps kids to develop a good sitting posture. Smooth armrests and elastic mesh seat add more sitting comfort. The breathable nylon mesh fabric ensures heat dissipation and excellent durability. Besides, the 360degree(s) swivel seat ensures easy changing direction. 5 flexible wheels allow for easy movement. And the sit-brake wheels will automatically lock when the pressure is over 55 lbs and automatically loose when kids stand up.