Desworthy Editorial Team
Desworthy editorial reviewer focused on ergonomic chair research, desk tech, affiliate disclosure, and practical UK home office buying decisions.
Last reviewed on by Desworthy Editorial Team.
Last Verified Date: 6 October 2026. Sources and model-specific claims checked; individual fit and final basket totals depend on your circumstances.
AI Summary
- There is no comparable published contact-force curve across the range, so a numerical force ranking would be invented.
- The verified distinction is control: manual height/depth on M57, moving support on C300, and two dynamic pads on S300. Source 3 Source 1 Source 2
- Choose the mechanism that lets you avoid a painful contact point, rather than buying from a marketing-word ranking.
Decision table
| Situation | Practical choice |
|---|---|
| You need to position the support yourself | Try the M57 manual controls. Source 1 |
| You want support to move as you recline | Sit-test the C300 and S300 under the same conditions. Source 3 Source 2 |
What to do
A defensible future ranking would use the same participants, seat height and recline angle, then record support position, contact area and a declared pressure measure. We have not verified a current UK M98C version or its comparable measurements, so it cannot credibly be placed at the "gentlest" end of a list.
Compare control mechanisms instead of an unsupported force score
| Model | Manufacturer-described fitting route | Useful question |
|---|---|---|
| M57 | Manual lumbar height/depth | Can the pad be positioned away from your pressure point? |
| C300 | Moving lumbar support | Does comfortable contact remain when you recline? |
| S300 | Two dynamic lumbar pads | Do both pads meet the intended lower-back area? |
The linked manufacturer pages support these mechanism descriptions; they do not supply a shared pressure scale. Do not convert words such as adaptive, dual or strong into force rankings. Start with the work posture you use most and change one setting at a time. Record whether the contact spreads across the lower back or concentrates on one point. Repeat in a comfortable recline, because the support path may matter as much as its upright position.
Choose M57 for a trial when manual positioning is your priority; compare C300 and S300 when following movement is the priority. Each choice remains conditional on an actual comfortable fit. There is no supported rule that a heavier user always needs a harder pad or that a slimmer user always needs a softer one. A spinal condition needs individual clinical advice, not a stronger-support marketing label.
Frequently asked questions
Is dynamic support always firmer?
Its mechanism name does not answer that.
Is stronger support healthier?
There is no universal rule of that kind.
Why is M98C not ranked?
Comparable current-version measurements are missing.
What if I have a spinal condition?
Do not choose a chair as treatment from a comfort ranking; seek clinical advice.
Sources and citation notes
Specifications and policies are attributed to their original publishers. Named hands-on reviews are attributed to the reviewer and the version reviewed. The decision advice is editorial synthesis, not a clinical, laboratory or transaction result. Check the exact version and current terms before buying.
- [1] SIHOO UK M57 specification
- [2] SIHOO UK Doro C300 specification
- [3] SIHOO UK Doro S300 specification
- [4] NHS slipped disc advice and emergency symptoms
Related UK buying guides
- Sihoo c300 lumbar support slim users
- Sihoo chair slipped disc workstation questions
- Current Sihoo UK offers
Compare before choosing this model
- M57 versus C300: manual and moving lumbar layouts
- B300 Pro versus C300: depth, width and support layout
Note: This article is for reference only.