I'm selling the VIVO dual monitor mount for $15. Product descriptions are copied below. It is already assembled and ready for use.

• Fits 13" To 27" Screens - Dual monitor mount fitting two screens 13” to 27” in size and 22 lbs in weight each.
• Articulation & Height Adjustment - Adjustable arm offers +90° to -90° tilt, 180° swivel, 360° rotation, and height adjustment along the center pole. Monitors can be placed in portrait or landscape orientation.
• Heavy Duty C-Clamp - Mounts to the back of your desk (up to 4” thick) via a heavy-duty C-clamp or optional grommet mount.
• Integrated Cable Management - Keep your power and AV cables clean and organized with detachable cable clips on the arms and center pole.