Verdicts here are built from published testing, real owner reports and spec sheets, not our own hands-on use. See how we judge →
A monitor arm is one of those upgrades you buy once and stop thinking about, if you pick the right one. Get it wrong and you will be re-clamping a wobbly arm every week. Here is what actually matters before you buy, based on published buying guides from BenQ and Micro Center.
Gas spring vs. mechanical arms
Gas-spring arms use a nitrogen-filled cylinder to counterbalance the monitor, so you can push or pull the screen into position with one finger and it stays put. Mechanical (spring-tension) arms are cheaper but stiffer, and usually need a screwdriver to adjust the tension. If you reposition your screen often, pay for gas spring. If you set it once and leave it, mechanical is fine.
Clamp, grommet, or wall mount
- Desk clamp: a C-shaped bracket that grips the desk edge. Works on almost any desk, easiest to install, and per Micro Center’s buying guide it is the right default for most people.
- Grommet mount: goes through a hole in the desktop. Cleaner look, handles thicker desks, but you need an existing or drillable hole.
- Wall mount: frees the desk entirely but needs to hit a wall stud, and moving it later means drywall repair.
Avoid clamping onto a hollow-core desk (the cheap flat-pack kind), both clamp and grommet mounts can damage them, per Micro Center.
Weight capacity: don’t just match it, beat it
Check your monitor’s weight (without its stand, usually listed on the manufacturer’s spec page) and add a safety margin. BenQ’s buying guide recommends an arm rated for at least 28.6–33 lbs (13–15 kg) as the most versatile choice for a standard monitor, since accessories like a monitor light or webcam add weight you need to account for.
Two mistakes to avoid in either direction: an under-rated arm will sag over time, and an over-rated heavy-duty arm can cause a lightweight monitor to float upward and refuse to stay down, per BenQ. If you run a curved or ultrawide display, add roughly 5 extra lbs of buffer. The curve shifts the weight forward and adds tension to the joint regardless of which arm you choose.
Check VESA compatibility before you buy anything
Nearly every monitor arm mounts via VESA: four screw holes in a square pattern on the back of your monitor. The monitors that sometimes lack it are older or very cheap models, so if you are running one of those, confirm VESA support before ordering an arm.
Single vs. dual monitor arms
For a two-screen setup, a dedicated dual-arm unit (one clamp, two arms) is simpler to install and easier to align side by side than running two separate single arms. The exception: if you want one screen to stay perfectly centered as your main display (common in gaming setups), two independent single arms give you more control over that.
The one-line version
Gas spring if you adjust often, mechanical if you don’t. Clamp mount unless you specifically want the cleaner grommet look. Size the weight rating up, not down. Confirm VESA before you buy. That is genuinely most of the decision.
How to read a monitor arm spec sheet
The headline numbers on a product page are only half the story. Here is what to look for, using two real spec sheets as worked examples: the Ergotron LX and the BenQ Ergo Arm (BSH01), both checked on the makers’ own pages on 27 September 2026.
- Both ends of the weight range. Ergotron lists 7 to 25 lbs for the LX; BenQ lists 4.4 to 44 lbs. The minimum matters as much as the maximum: a monitor lighter than the bottom of the range can make the arm drift upward.
- The fine print under the weight. Ergotron notes that with a monitor over 20 lbs, the LX can lose up to 4.5” of height travel, and that a monitor deeper than 3.5” may reduce capacity. Look for notes like these on any arm near its limit.
- Tilt in each direction, not the total. The LX tilts 70° back and 5° forward. The BenQ tilts 50° up and 20° down. Similar totals, very different use: one suits a screen angled up, the other a screen angled down toward you.
- Desk thickness, with and without extras. The LX clamp takes 10 to 60 mm. The BenQ takes 17 to 50 mm on its own and 12 to 45 mm with its reinforcement plates fitted. Measure your desk at the exact spot you will clamp.
- Reach. BenQ lists up to 568 mm, about 22.4 inches, of extension. If your desk is deep and the clamp sits at the back edge, reach decides whether the screen can come close enough.
- Warranty. Ergotron states 10 years for the LX. A long warranty on a gas spring arm is the maker betting the spring will not sag.
A five-minute check before you order
- Find your monitor’s weight without its stand on the maker’s spec page, then add anything you will mount on it, such as a webcam or monitor light.
- Check the four holes on the back of the screen and note the VESA pattern, usually 75 x 75 or 100 x 100 mm.
- Measure the desk thickness where the clamp will go, and look underneath for a frame rail or drawer that would block it.
- Measure from the back edge of the desk to where you want the screen to sit. That is the reach you need.
- Compare all four numbers with the arm’s spec page. If any is at the edge of a range, pick a different arm.
Ready to choose? Our best monitor arms of 2026 list puts these checks against real picks.