Ergotron WorkFit-A, Dual (24-257-026) On-demand sit-stand workstation - improve your energy and productivity by standing or sitting as you work, and then switch positions whenever you choose. Standing a little more each day burns extra calories, tones muscles. Safe, easy-to-use - simple installation and effortless operation. Easily and simultaneously lift keyboard and screens to proper height for unsurpassed ergonomic comfort.