Clamps to the edge of the desk. Adjustable to customize sitting and standing work positions to be as comfortrable as possible and reduce neck/back/wrist pain and fatigue. Extemely sturdy design with large 26-1/2 x 9" keyboard/mouse tray. Gas spring arm instantly moves keyboard to any height. Monitor up to 27" and 24 lbs can slide up and down the column for optimal viewing up to 36".above your desk, and rotate 180 degree for landscape or portrait orentation. Enitre unit swivels at any angle. Cover by Lorell Limited 5-Year warranty.