HX Monitor Arm

The HX is the most physically substantial arm in our lineup, and it feels it. Built from aluminum and steel around Ergotron’s Constant-Force mechanical spring, it’s engineered to hold a 42-pound display motionless — and the practical result is zero sag and zero drift even with a large, heavy ultrawide hanging off the end, a load that would defeat any standard arm. Reviewers consistently describe it as tank-grade, and the construction backs that up: it passes Ergotron’s 10,000-cycle motion test and carries the same 10-year warranty as the LX.

This is the same proven engineering philosophy that makes the LX our #1, scaled up for heavier duty. Where a budget gas-spring arm relies on a pneumatic cylinder that can soften over the years, the HX’s mechanical spring holds its set tension indefinitely — which matters even more on a heavy screen, where any loss of counterbalance shows up immediately as droop.

It earns 9.5 rather than a perfect mark for the same reason the LX does: the milled-aluminum premium tier (Ergotron’s own MX, the design houses) edges it on finish and joint refinement. None of them is more stable than the HX — for raw rigidity under heavy load, this is as good as it gets.

Bottom line on stability: Tank-grade build and a 10-year warranty, with the Constant-Force spring holding a 42-pound screen without a hint of sag. The most rigid arm in the lineup.

The HX has an excellent range on paper: 23.6″ of extension, 11.5″ of height lift, 75° of tilt, full 360° rotation for portrait, and the ability to fold back within six inches of the wall for a tidy parked position. For a heavy-duty arm, that’s genuinely flexible — you can push a 49″ ultrawide back to a comfortable distance or pull it forward, then tilt and angle it freely.

It scores a notch below the LX here for two honest reasons. First, the numbers are marginally tighter — 11.5″ of lift versus the LX’s 13″ — because lifting a much heavier screen through the same travel is a harder engineering problem. Second, and more importantly, the spring is tuned for 20-to-42-pound loads. With a heavy display it feels smooth and planted; but the heavier counterbalance means the fingertip-light effortlessness of the LX under a normal monitor isn’t quite the experience here. The HX rewards the screen it was built for, and feels stiff with anything lighter.

Bottom line on motion: A wide, flexible range built for big screens — 23.6″ reach, 11.5″ lift, full tilt and rotation — just tuned for heavy loads, so it’s less effortless than the LX under a standard monitor.

This is the HX’s reason to exist, and it’s the only perfect sub-score in our entire 12-arm ranking. The arm is rated for 20 to 42 pounds and screens up to 49″ — the largest ultrawides on the market, including curved panels — and it supports the full span of VESA patterns from 75×75 all the way to 200×200 mm, which the big professional and ultrawide displays often require and which standard arms simply don’t carry.

Put concretely: where our #1 LX tops out at 25 lb and 34″, the HX nearly doubles the weight ceiling and adds fifteen inches of screen. A 49″ Samsung Odyssey-class ultrawide, a 40″ 5K2K panel, a heavy color-grading monitor — these are exactly the displays that make a normal arm droop within days, and the HX holds them as if they were lightweight. Nothing else we tested comes close on raw capacity.

The one thing to internalize is that this strength is also a constraint: the 20-pound floor means the HX is built for heavy screens specifically. A typical 27″ monitor weighs 10 to 15 pounds — below the HX’s comfort zone — so this capacity is a perfect 10 only if you actually have a display that needs it.

Bottom line on capacity: A flawless 10 — 42 lb, 49″ ultrawides, and the widest VESA support in the lineup. The clear and only choice for genuinely large or heavy displays.

The HX ships with both a C-clamp and a grommet mount in the box, and Ergotron also sells the same arm in a dedicated wall-mount version for setups that can’t use the desk. The hardware and instructions are the well-organized Ergotron standard, and the clamp anchors solidly — which it has to, given the loads involved.

Installation scores a bit lower than the LX’s for practical reasons that come with the territory. The HX is heavier and bulkier to assemble, and mounting a 40″-plus, 30-pound ultrawide onto it is genuinely a two-person job — one to hold the screen, one to seat and tighten the VESA bracket. It’s not difficult, but it’s more of an undertaking than clipping a light monitor onto an LX. Make sure your desk is sturdy enough to take both the clamp force and the cantilevered weight of a big screen at full extension, too.

Bottom line on installation: Clamp, grommet, and wall-mount options with solid Ergotron hardware — just heavier to handle, and big-screen mounting is realistically a two-person job.

Cable management mirrors the rest of the Ergotron line: integrated clips and channels run the monitor’s power and video cables along the arm and post, keeping them controlled through the full range of motion so nothing snags as you extend or rotate a large screen — which matters more here, since ultrawides often carry thicker cable bundles and sometimes a separate power brick.

As with the LX, it’s a tidy clip-and-channel approach rather than a fully enclosed cable tunnel, so the 8.5 is identical to its sibling’s. For a heavy-duty arm the routing is more than adequate, and it handles the bulkier cabling of big displays without complaint.

Bottom line on cables: The same effective integrated clip-and-channel routing as the LX, well suited to the thicker cabling that big ultrawides bring.

This is the HX’s only amber score, and it’s a deliberate, honest one. The arm carries a real premium — it’s one of the most expensive single arms in our lineup — and it’s a specialist tool. Bought for the display it’s designed around, a heavy 38″-plus ultrawide or a 30-pound professional panel, it’s worth every dollar: it’s the only arm that holds those screens properly, and a 10-year warranty makes it a buy-once proposition. In that context the value is fine.

The 6.5 reflects how poorly that math works for the wrong buyer — which, for a typical home office, is most buyers. If your monitor is a standard 24″ to 32″ panel under 20 pounds, the HX is the wrong arm: you’d pay a heavy-duty premium for capacity you can’t use, on a spring that feels stiff with a light screen. For that setup the LX (our #1) or the Ergotron-built Amazon Basics arm (our #2 Best Value) does the job better for far less. We score Value against the whole field, and as a general-purpose arm the HX is poor value — even though it’s exactly right for its niche.

Bottom line on value: Excellent value if you have a heavy or ultrawide screen that needs it; poor value if you don’t. Match the arm to the display — don’t buy this much capacity for a standard monitor.