Use the Rapid Riser on an existing fixed height desk to allow sit and stand height adjustable operation | With large keyboard tray and wide work surface, gas spring height adjustment via control levers either side allowing 15 height adjustment levels | Height adjustment from 150mm to 500mm | Weight capacity up to 18kg | Easy manual operation | Available in Small or Medium size | Large Keyboard Tray and Wide Work Surface | Gas Spring Offers Smooth and Even Height Adjustment | 15 Height Adjustment Levels | Sits on Existing Workstation | Control Levers on Either Side