Twixt Desk Height Ergonomic Stool, Supports Up to 250 lb, 22.5" Seat Height, Green Seat, Black BaseHeight adjustable, active seating solution that provides ergonomic posture to users. Design is a symmetrical balance between the base and top, giving it a sleek look, which sets it apart from traditional seating and other similar seating options. Features an upholstered seat that swivels on an aluminum base. Base is designed with a flexible ring underneath to allow the user to adjust the angle to provide a chair where the user can perch, lean or sit.