This is an ACCURTEK LDT23-C012 monitor arm. I used it to mount a 40-inch 4K monitor for several years, and it held up well. According to the manufacturer, it's a gas spring-assisted heavy-duty arm that supports monitors from 17 to 49 inches and up to approximately 18kg. It's designed to move smoothly up, down, and forward with minimal effort. It also has a safety screw to prevent the arm from extending too far behind the desk. There is a tear in the cushion (foam part) on the underside of the base (see photo). I have kept the screws as organized as possible, but I haven't reassembled it to confirm that all the accessories are present. Please understand this before purchasing.