Sold as 1 Each. Each arm holds a monitor up to 27 in. and 13 lbs. Easy to mount via grommet hole allowing for quick set-up. Height adjusts up to 16 in. above the top surface of the Lotus Sit Stand Workstation with a reach of 12.5 in. 3-year limited warranty. Meets VESA mounting standards. 16.50 in. H x 28.50 in. W x 5.50 in. D.