A monitor arm improves posture, desk space and cable routing at the same time. It is also easy to buy in the wrong specification, because the three numbers that decide compatibility are not the ones on the product photo.
Measurement 1: VESA pattern
VESA is the square of four screw holes on the back of your monitor. Two sizes cover almost everything:
- 75 x 75 mm — smaller and older screens
- 100 x 100 mm — most 24 to 32-inch monitors
Measure centre-to-centre between the holes, horizontally and vertically. If your monitor has no visible holes, it may still be VESA-compatible behind a clip-off cover — check before assuming it is not.
Some slim and curved monitors use a proprietary mount and need an adapter plate. Confirm this first; it is the single most common reason an arm arrives and cannot be fitted.
Measurement 2: screen weight, with everything attached
Every arm has a working weight range, and both ends of it matter.
Too heavy is obvious — the arm sags or will not hold position. Too light is the failure people do not expect: a gas-spring arm rated 4–12 kg will fling a 3 kg monitor upward, because the spring is pushing harder than the screen weighs. Many arms have a tension screw with enough range to fix this, but not all do.
Weigh the monitor without its original stand. A 24-inch panel is usually 2.5–4 kg; 27-inch is 4–7 kg. Manufacturer spec sheets often quote weight with the stand, which can be double.
Measurement 3: desk edge thickness
The one everybody forgets. Most clamps handle a desk edge of roughly 10–40 mm. Measure the actual lip your clamp will grip, not the thickest part of the desk.
Two things to check as well:
- Is the edge solid? A clamp needs 60–80 mm of unobstructed depth. Rails, drawers and reinforcing bars under the lip will block it.
- Is the surface glass? Clamping glass is possible but needs the manufacturer's blessing and a wide pad. If in doubt, don't.
Gas spring or friction?
Gas spring holds the screen by counter-balancing its weight. You move it with one hand and it stays. Better if you actually reposition your screen — sitting, standing, turning it for someone.
Friction (bolt-tightened) holds by clamping tight. Cheaper and rock solid, but repositioning means loosening a bolt. Fine if you will set it once and forget it.
If you are unsure, gas spring. The ability to push a screen back 15 cm mid-session is worth more than it sounds.
Clamp or grommet?
Clamp grips the desk edge — no drilling, and reversible. Grommet passes a bolt through a hole in the desk, which is more rigid but permanent.
Clamp for almost everyone. Grommet if your desk has no accessible edge, or if you are mounting something heavy at full extension.
Dual arms: the mistake to avoid
A dual arm concentrates two monitors' weight into one clamp point. On a thin or particleboard desk this can dish the surface over months.
If your desk is under 18 mm or is hollow-core particleboard, use two single arms at separate clamp points instead of one dual arm. Same result, half the load per point.
Also check total reach: two 27-inch screens on one central post need considerably more arm span than the product images suggest.
Quick pre-purchase checklist
- VESA pattern measured — 75 or 100 mm
- Monitor weight without stand, inside the arm's range at both ends
- Desk edge thickness, and 60–80 mm of clear depth for the clamp
- Nothing underneath blocking the clamp
- Decided gas spring vs friction based on how often you will move it
What it gives you back
Removing a factory stand recovers 20–25 cm of desk depth. On a 60 cm desk that is a third of the surface, and it is usually the difference between a screen at the right distance and one you are sitting too close to.
Arms and stands are in Setup Accessories. If you would rather not measure anything, we fit them as part of installation in Cairo and Giza.
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