Ergotron 24-312-026 Mounting Arm with 19.5-Inch Height Adjustment Improve your energy and productivity by standing or sitting as you work. Safe, easy-to-usecomes fully assembled and offers effortless operation Easily and simultaneously lift keyboard and screens to proper height for unsurpassed ergonomic comfort On-demand sit-stand workstation-improve your energy and productivity by standing or sitting as you work, and then switch positions whenever you choose. Safe, easy-to-use-comes fully assembled and offers effortless operation Easily and simultaneously lift keyboard and screens to proper height for unsurpassed ergonomic comfort