Fits one computer screen 17 19 21.5 24 27 32 35 inches, with a maximum support weight of 33 pounds. Comes with interchangeable C-clamp or grommet base mount for use on desktops up to 3.3 inches thick. Comes with (2) USB 3.0 and (1) set of audio ports. Comes with an external VESA extension adapter, so mount will fit 75x75, 100x100, 200x100, and 200x200mm VESA patterns found on the back of your display. If unsure of size, measure the distance between the bolt holes in millimeters. Single arm monitor mount has a gas spring arm that can be adjusted using the included hex key in order to perfectly counterbalance the weight of your monitor. This makes for effortless height adjustments. Mounting head can tilt up 45 degrees and down 45 degrees, swivel and full 360 degrees, and monitor can be rotated 90 degrees left or right for portrait and landscape orientations. Gas spring arm can height adjust a total of 22 inches. Comes with a 5-YEAR WARRANTY and our US-based customer service