Adjusts up and down with the push of a button. Height ranges from 5-1/4" to 17-1/8" off your worksurface. Medical-grade electric motor provides a quick-release, low-noise operation. Anti-collision function will stop the up/down motion if desk riser meets objects like coffee cups or bottles. The top surface (31-1/2" x 24-2/5") includes USB interface for convenient connection and holds monitors up to 33 lb. Keyboard tray is large enough for a keyboard and mouse. Black.