Ergotron – LX Vertical Stacking Dual Monitor Arm, VESA Desk Mount – for 2 Monitors Up to 40 Inches, 7 to 22 lbs Each – Tall Pole, Matte Black

Why it's worth it

For a two-monitor setup on a desk that isn't especially wide, stacking beats sitting screens side by side. This puts two full LX arms on a shared 23-inch pole, each with its own 13 inches of lift, for screens up to 40 inches and 22 pounds apiece.

Stacking wins when desk width is the constraint. Side-by-side dual arms spread across your whole desk and force you to swivel your head all day. Going vertical keeps both screens in front of you and leaves the flanks of the desk free. Developers and traders tend to land here: a wide landscape panel up top, a portrait terminal below, or the reverse.

These are two proper LX arms, not a compromised pair. Each gets 13 inches of independent lift, and the top screen can rise as high as 31.7 inches above the desktop. Each arm handles up to 40 inches and 22 pounds, with 360-degree rotation and 75 degrees of tilt. You can also position the screens side by side if you change your mind later.

From our review of 12 monitor arms and desk mounts, by Ben Carter, Tech Editor

What we like

• +Stacking wins when desk width is the constraint
• +These are two proper LX arms, not a compromised pair
• +Everything you need ships in the box

What to know

• –It's the most expensive item in this guide
• –The 22-pound per-screen limit is lower than the single LX's
• –Getting the stack to look right takes patience