Turns any seated workstation into a sit-stand workstation. Easy to use, with gas assisted height adjustment, and infinite height settings. Easy adjustments with two knobs. Primary work surface can be extended 20 in above the desk. Accommodates two 24 in monitors. +/- 10° keyboard surface tilt. Supports up to 30 lb. Independent keyboard and mouse surface. Fully assembled. Primary work surface is 35.5 x 15.75 in. Sold by each.