The Rocelco Height Adjustable Sit to Standing Desk Riser and Comfort Floor Mat Bundle offers the versatility you need to get through your work day. Now you can sit part of the day or stand to take advantage of all the health benefits that come with standing and moving around. With the desk converter, you and your associates will become healthier and more productive. It fits over your current desk with no need to buy additional furniture. With its spacious 42.9" W x 20.5" D work surface, you can hold up to 2 large monitors, a laptop, and more. It also includes an extra large keyboard tray that measures 34.8" W x 10" D that is an ergonomic 4" below the desktop. Quick-disconnect keyboard tray allows portable use. Enhanced Vertical Range rises up to 21.7" and down to 4.7", to optimize the ergonomic work position for people of all heights. Straight up and down motion minimizes required depth (18.5"). Gas piston assist allows you to easily raise and lower up to 33lbs. 10.5" wide slot holds tablet or phone. Desk riser is fully assembled and ready to go! The included Anti-Fatigue comfort floor mat is designed to work in tandem with standing desk risers. It will help support your back, hips, knees and feet so you can get all the benefits of standing while you work. This versatile desk mat effectively "reduces" your weight by 30% to make standing easier on your feet and joints.