Ergotron LX vs HX vs MX: Which Monitor Arm Is Right for You?

The short answer to Ergotron LX vs HX vs MX: choose the LX for most monitors under about 19 lbs, the HX for heavy ultrawides and large displays up to 42 lbs, and the MX when you need extra reach or premium materials. They look almost identical from across the room, but each is built for a specific weight and screen-size range, and picking the wrong one means sag or a wobbly arm.

Below is the full spec breakdown, the curved-monitor caveats, and a decision tree so you can match the arm to your exact monitor.

Ergotron LX vs HX vs MX at a glance

Spec	LX	HX	MX
Weight capacity	7–19 lbs	20–42 lbs	6–30 lbs
Screen size	up to 34”	up to 49”	up to 32”
Reach	25”	25”	35”
VESA	75×75, 100×100	100×100, 200×100, 200×200	100×100
Tilt	75° / 5°	75° / 5°	70° / 5°
Warranty	10 years	10 years	10 years
Best for	most monitors under 19 lbs	heavy ultrawides up to 42 lbs	long reach, premium build

Choose the LX for most monitors under about 19 lbs, the HX for heavy ultrawides and large displays up to 42 lbs, and the MX when you need extra reach or premium materials.

Quick Verdict by Monitor Type

• 24–32 inch flat or curved, under 19 lbs: Ergotron LX ↗ (Amazon Associates). The default, the most common, the one you should buy if you don’t have a reason to upgrade.
• 32–43 inch curved or heavy-gaming, 20–42 lbs: Ergotron HX ↗ (Amazon Associates). The upgrade path for heavy ultrawides.
• 38–49 inch ultrawide or super-ultrawide, up to 42 lbs: Ergotron MX ↗ (affiliate). Long reach, low post profile, premium build.

Ergotron LX — The Default

The LX is Ergotron’s mid-range single-arm and one of the best-selling monitor arms in the western market. It uses Ergotron’s Constant Force tension system, a gas-spring-style internal mechanism that holds position without thumbscrews (see gas spring vs mechanical spring arms for why that matters), and supports monitors from 7 to 19 lbs.

Spec sheet:

• Weight capacity: 7–19 lbs (3.2–8.6 kg)
• Screen size: up to 34” (Ergotron’s official spec; owners commonly report mounting 38” ultrawides that stay under the 19 lb limit)
• Vertical adjustment: 13” range
• Reach (from pivot to screen): 25”
• Tilt: 75° (back) / 5° (forward)
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 75×75, 100×100
• Warranty: 10 years
• Color: matte black, polished aluminum, white

Where the LX excels:

• Constant Force tension is genuinely set-and-forget. Once tuned to your monitor, it stays in position for years.
• Mounting hardware accommodates both desk clamp (1.4”–2.4” desktop thickness) and grommet mount (0.4”–2.4”).
• Replacement parts are available individually, and the warranty is honored without drama.

Where it falls short:

• 19 lb capacity is below many heavy 32-inch curved gaming monitors. The MSI MAG 321CUP weighs 22 lbs; LG 45GR95QE-B weighs 36 lbs. Both are too heavy.
• Reach is 25” — adequate for desks 27”+ deep, marginal for shallow desks.

Buy: Ergotron LX (matte black) on Amazon ↗ (Amazon Associates). Polished aluminum and white finishes are available; pricing is identical.

Ergotron HX — Heavy-Duty Single

The HX uses the same Constant Force mechanism but with a stronger spring and beefier joints. Capacity nearly doubles to 42 lbs.

Spec sheet:

• Weight capacity: 20–42 lbs (9–19 kg)
• Screen size: up to 49”
• Vertical adjustment: 13” range
• Reach: 25”
• Tilt: 75° / 5°
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 100×100, 200×100, 200×200
• Warranty: 10 years
• Color: matte black, polished aluminum, white

Where the HX excels:

• Handles the heaviest single-monitor setups on the market. Its rated 42 lb capacity covers 49-inch ultrawides like the ~36 lb Samsung Odyssey G9 with margin to spare, which is the class of display owners most often report pairing with the HX.
• Supports VESA 200×200, which most large displays require.
• Same intuitive Constant Force tension as the LX.

Where it falls short:

• For monitors under 20 lbs, the HX is overkill. The Constant Force spring requires a minimum load to work properly — a 12-lb monitor on an HX may droop or fail to hold position.
• Costs ~50% more than the LX.

Buy: Ergotron HX on Amazon ↗ (Amazon Associates).

Ergotron MX — Long Reach, Premium Build

The MX is the premium pick. Same Constant Force system, but the build is meaningfully nicer — milled-aluminum joints rather than cast, a longer reach arm, and a low-profile post designed for tight under-shelf clearance.

Spec sheet:

• Weight capacity: 6–30 lbs (2.7–13.6 kg)
• Screen size: up to 32” (modern variant; older MX supports up to 24”)
• Vertical adjustment: 13” range
• Reach: 35” (longest of the three)
• Tilt: 70° / 5°
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 100×100
• Warranty: 10 years
• Color: matte black, polished aluminum

Where the MX excels:

• 35” reach is genuinely useful for desks where the monitor needs to push back further than the LX/HX can reach (deep desks, wall-mount-style setups).
• Low post profile (~11 inches above desktop) clears under-shelf and overhead lighting setups better.
• Material quality is noticeably better in person than LX/HX.

Where it falls short:

• VESA 100×100 only — won’t mount the largest displays.
• 30 lb capacity caps it below the HX.
• Costs about 2x the LX.

Buy: Ergotron MX direct ↗ (affiliate).

The Decision Tree

Ask three questions in order:

1. Is your monitor over 19 lbs? If yes → HX. If no, continue.
2. Do you need over 25 inches of reach? If yes → MX. If no, continue.
3. Do you have a budget constraint? → LX.

99% of single-monitor home office users buy the LX. The HX is for heavy ultrawide or large display users. The MX is for users with specific reach/clearance requirements or premium-materials preferences.

Curved Monitor Caveats

Curved monitors complicate VESA mounting. The center of gravity is closer to the screen face than on a flat monitor, which puts unusual torque on the arm joint.

• For curved monitors with 1500R or shallower curvature, no adjustment needed.
• For 1000R or deeper (like Samsung Odyssey or LG UltraGear curved): consider a VESA spacer adapter. The standard Ergotron mount works but the screen tilt range is reduced.
• 49” super-ultrawide curved displays: HX only, and use a VESA reinforcement plate. The pivot point is far enough from the screen center to create persistent sag without a reinforcement.

For a wider field of options beyond Ergotron at this size, see the dedicated ultrawide and heavy monitor arm guide.

Dual-Monitor Setups

None of these arms is a dual-monitor arm by default. For dual monitors, see:

• Ergotron LX Dual Side-by-Side ↗ (Amazon Associates): two LX arms on one post. Best for two 24-inch monitors.
• Ergotron LX Dual Stacking ↗ (Amazon Associates): vertical stacking, useful for trading-style setups.
• For two monitors over 19 lbs each: two separate HX arms, mounted independently.

What About Non-Ergotron Alternatives?

Several brands compete with Ergotron:

• Herman Miller Flo Plus: Cleaner aesthetic, more expensive, capacity is 22 lbs (between LX and HX). For a closer look, see Herman Miller Flo vs Humanscale M2 vs Ergotron LX.
• Humanscale M2.1/M8.1: Best-in-class joint smoothness, very expensive, lower capacity than Ergotron’s lineup.
• Fully Jarvis: Budget alternative, ~$100 cheaper than LX, build quality is one step below.
• Amazon Basics Premium Monitor Arm: Surprisingly competent for the price (~$80), but only 17 lbs capacity and shorter warranty.

For most users, Ergotron is the right pick — the LX in particular. The 10-year warranty, parts availability, and the Constant Force mechanism are difficult to beat at the price.

Related Reading

• How to choose a monitor arm — the full buying decision
• VESA compatibility explained — mounting patterns and adapters
• Sister site StandDeskReview ↗ — for the desks these arms attach to
• Sister site ErgoRanker ↗ — for spec-driven ergonomic rankings

Final Word

If you’re stuck deciding between Ergotron LX, HX, and MX, the answer is almost certainly the LX. The HX exists for heavy ultrawides; the MX exists for long-reach and premium-material requirements. Most home offices need neither.

Specs verified May 2026. Pricing is approximate manufacturer/Amazon listing as of publication.