Herman Miller Flo Review: Which Flo Do You Actually Need?
Flo is five different arms with different weight ratings, not one product. How to pick correctly, and why the minimum weight matters as much as the maximum.
“The Herman Miller Flo” is not a product. It is a family of at least five different arms with materially different weight ratings, and buying the wrong one is the most common way this purchase goes wrong.
This is a research-based review using Herman Miller’s published specifications. We have not tested these arms ourselves and do not claim to have. Our review standards.
The short answer
Weigh your monitor with the stand removed, then pick the arm around that number.
2–7 kg (most 24in and many 27in panels) → Flo, Flo Dual or Flo Modular.
Above 7 kg, or a screen over 34in → Flo X, rated 3–18 kg and up to 43in.
Get this wrong in either direction and the arm will not hold position. Too heavy and it sags; too light and it floats upward.
Which Flo is which
| Model | Weight range | Max screen |
|---|---|---|
| Flo (single) | 2–7 kg (4.4–15.4 lb) | Up to 34in |
| Flo Dual | 2–7 kg per screen | Up to 34in each |
| Flo Modular | 2–7 kg per arm | Up to 34in, flat or curved |
| Flo X Single | 3–18 kg (7–40 lb) | Up to 43in |
| Flo X, one spring disengaged | 3–9 kg | Up to 43in |
All designed by Colebrook Bosson Saunders for Herman Miller.
The minimum is as important as the maximum
Almost everyone checks whether their monitor is under the maximum. Very few check whether it is over the minimum, and that is the failure people describe as “the arm won’t stay down”.
A gas or mechanical spring arm is a balance. The spring pushes up with a force you set; the monitor pulls down with its weight. When the two match, the screen stays wherever you leave it — that is the whole trick.
If your monitor weighs less than the arm’s minimum, the spring is stronger than the load even at its weakest setting. The screen drifts upward and no amount of adjustment fixes it, because you have run out of adjustment.
Why the Flo X dual spring is genuinely clever
The Flo X uses two springs and lets you disengage one, which drops its range from 3–18 kg to 3–9 kg.
That is a direct answer to the problem above. A single arm engineered to hold a 40 lb screen would normally be hopeless with a light one — too much spring, no matter how far you wind it down. Switching one spring out narrows the band so a lighter monitor can still be balanced properly.
It also means one arm can survive a monitor upgrade in either direction, which few arms manage.
Check the VESA pattern and the mount before you buy
Two things quietly disqualify arms after they arrive.
VESA. Most monitors use 75 × 75 mm or 100 × 100 mm hole patterns. Some, particularly thin consumer panels and certain curved ultrawides, have no VESA mounting at all, or need a manufacturer-specific adapter plate. Look at the back of your monitor before ordering anything.
The desk. Clamp mounts need an accessible desk edge of the right thickness with nothing underneath. Grommet mounts need a hole. A desk with a full-width back panel, a thick rounded edge, or a drawer immediately below can defeat either.
What a monitor arm actually gets you
The ergonomic case is straightforward: the top of the screen should be at or just below eye level, at roughly arm’s length. Almost no factory stand goes high enough for a tall person, and stacking books is a workaround rather than a fix.
The second benefit is the desk underneath. A stand occupies the most useful area of the desk; an arm returns it.
The third is being able to move the screen at all — pull it forward for detailed work, push it back for a call, turn it to show someone. Most people discover they use this more than they expected.
Flo or Ergotron LX?
| Herman Miller Flo | Ergotron LX | |
|---|---|---|
| Weight range | 2–7 kg (18 kg on Flo X) | 3.2–11.3 kg |
| Max screen | 34in (43in on Flo X) | Up to 34in |
| Horizontal reach | Shorter | Up to 24in |
| Range options | Five models to choose from | One, plus an extension |
The honest summary: the Ergotron reaches further and its single model covers a wide weight band, which makes it simpler to buy. The Flo family lets you match the arm more precisely to the screen, at the cost of having to choose correctly. Our Ergotron LX review covers tension setting, which is where people go wrong with either.
What this review cannot tell you
We have not mounted these arms, tested stability under load, assessed long-term spring behaviour, or checked fit on specific desks. All figures are Herman Miller’s published specifications. The spring-balance explanation describes how counterbalanced arms work generally rather than a measurement of these units.
Frequently asked questions
Which Flo do I need?
Weigh your monitor with the factory stand removed. Between 2 and 7 kg, the standard Flo, Flo Dual or Flo Modular. Above 7 kg or over 34 inches, the Flo X, which handles 3–18 kg and up to 43 inches.
My monitor floats upward and won’t stay down. Why?
It is almost certainly lighter than the arm’s minimum rating. The spring is stronger than the load even at its lowest setting, so no adjustment can fix it. You need an arm with a lower minimum.
Do I weigh the monitor with its stand?
No — remove the factory stand first. It is often a third of the total weight and is not going on the arm.
What is the Flo X dual spring for?
You can disengage one of the two springs, dropping the range from 3–18 kg to 3–9 kg. It lets one arm handle both heavy and fairly light monitors properly.
Will it fit my monitor?
Check the back for a 75 × 75 mm or 100 × 100 mm VESA pattern. Some thin consumer panels have none, or need a manufacturer adapter plate.
Flo or Ergotron LX?
The Ergotron reaches further and covers 3.2–11.3 kg in one model, so it is easier to buy. The Flo family matches the arm more precisely to the screen, provided you pick the right one.
- Ergotron LX monitor arm
- AOC Q27G3XMN — a monitor to put on it
- Gigabyte M27Q X
- Docks for the same desk
Sources. Weight ranges, maximum screen sizes, model variants and the Flo X dual-spring behaviour are Herman Miller’s published product specifications. Ergotron LX figures are Ergotron’s published specifications. We have not tested these arms ourselves. Primary source: Herman Miller’s Flo monitor arm range.