Choose a single monitor arm if only your notes screen needs mounting or repositioning beside the presentation display. Choose a dual arm if both screens need to be mounted and adjusted from one desk attachment. Either way, check each screen’s installed weight, mounting pattern and movement clearance against the exact arm before buying; an arm alone will not settle the wider workstation layout or establish how quietly it moves.
If your presentation screen can stay where it is, a single arm lets you assess the position of the notes display independently. Dell’s MSA20 and the reviewed Ergotron LX are examples of single-arm designs with adjustable positioning.
If you want the presentation and notes screens off their original stands, assess a dual arm such as Dell’s MDA20. Both displays must fit the chosen system’s limits, and the desk must accommodate its attachment.
If you spend extended periods at the desk, screen placement matters alongside the chair, keyboard and other equipment. The UK Health and Safety Executive advises positioning the top of the screen at eye level and the screen about an arm’s length away.
Start by deciding whether one display or both need mounting. Then check the monitor and desk against the exact arm before planning where the notes screen will sit.
Choose it when: the presentation display can stay in place and only the notes screen needs independent movement.
Trade-off: it mounts one screen, so it will not lift both displays from their original stands.
Choose it when: both the presentation and notes displays need mounting and adjustment from one desk-based system.
Trade-off: each display must meet the dual model’s limits; Dell lists 19–27 inch displays for the MDA20, which differs from its MSA20 single-arm specification.
| Concern | What to check | Who this matters to |
|---|---|---|
| Notes-screen position | Check the arm’s height, reach and available movement clearance for your side-by-side layout. | If I need to glance at notes without placing them in front of my presentation, independent screen movement is my priority. Around 38% of consumers put notes-screen positioning first. |
| Monitor and desk fit | Match the installed screen weight and VESA mounting pattern to the exact arm; check whether the desk suits its clamp or grommet attachment. | A side-by-side layout is of little use to me unless the monitor and desk can take the attachment. Compatibility comes first for around 31% of consumers. |
| Viewing position | Plan screen height and distance alongside the main display and keyboard. The Health and Safety Executive advises an eye-level screen top and a viewing distance of about an arm’s length. | When I work at the desk for long periods, I want the notes screen readable without neglecting the rest of my workstation. Around 31% of consumers prioritise that wider viewing setup. |
A stated screen-size range does not establish that an arm can support your monitor’s weight or match its rear fixing points. Dell lists different screen-size specifications for the MSA20 and MDA20.
Check the installed monitor weight and VESA pattern against the exact model, then confirm the desk attachment and space for movement.
Both screens must fit the dual model’s stated limits. Dell’s MDA20 technical specifications list 19–27 inch displays; the MSA20 single-arm screen range cannot simply be applied to it.
Check each display separately, then assess the complete desk-mounted arrangement.
Adjustment features do not establish a noise advantage between arms. The Health and Safety Executive also treats display placement as one part of the whole workstation.
Plan the main screen, notes screen, keyboard and movement clearance together; do not rely on an unsupported claim of silent operation.
Ergotron identifies the reviewed LX 45-241-224 as discontinued and points to the newer LX Pro range. The older model’s specifications do not establish those of its replacement.
If you are considering LX Pro, check that variant’s own load range, mounting options and dimensions.
Dell offers separate MSA20 single-arm and MDA20 dual-arm routes for a desk with presentation and notes displays.
The reviewed LX Desk Mount is relevant if your notes screen needs substantial adjustment and uses a compatible VESA mount.
The M2 Pro is a route to assess for a lighter notes monitor, provided the chosen configuration matches the screen and desk.
Use a single arm if only the notes display needs mounting or repositioning. If both displays need to be mounted from one desk-based system, consider a dual arm and check the limits for each screen.
Check the monitor’s installed weight without its original stand, its VESA fixing pattern, the desk attachment and the clearance needed for movement. For the specific models reviewed, Dell lists 2.22–9.98 kg and a 100 × 100 mm pattern for the MSA20, while Ergotron lists 3.2–11.3 kg and 75 × 75 mm or 100 × 100 mm VESA support for the older LX model.
No. An arm can help you position a screen, but the Health and Safety Executive advises considering the whole workstation, including its furniture, equipment and work conditions. Its posture guidance places the top of the screen at eye level and the screen about an arm’s length away.
A personal, non-work purchase is not by itself an employer workstation assessment. For work, the UK Health and Safety Executive says display-screen equipment requirements apply to employers whose workers regularly use it as a significant part of their normal work; its workstation guidance considers the whole setup, not just a monitor arm.