LX Dual Stacking Arm, Tall Pole - Includes two LX arms and extensions, 23' pole, heavy-duty two-piece desk clamp base with dual screws, two pole collars, two caps, grommet mount plate and hardware, monitor mounting hardware To facilitate stacking of monitors, maximum outside height of display should be no more than 21' (53 cm). To align monitors side by side, maximum outside width should be no more than 40' (102 cm). Most monitors with screen sizes of 40' or less fit within this specification Mounting Standards: VESA FDMI MIS-D, 100/75, C (hole pattern: 100 x 100 mm & 75 x 75 mm) Desk clamp attaches to surface edge up to 2.6' (66 mm) thick Grommet mount attaches through hole 0.31' to 2' (8-50 mm) wide and up to 3' (76 mm) thick