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.
Source information was checked on 7 October 2026. The editorial update date above does not mean prices, availability or retailer terms were checked again. Confirm those details with the retailer before buying.
The S100 is the sensible starting point if you want a mesh chair with dual moving lumbar support and do not have a specific need for S300’s seat slide or recline mechanism. Choose S300 when those controls solve a fit or movement problem you can name. Its higher price does not buy a greater published recline angle.
At the checked UK listings, S100 Black was £259.99 and S300 Black was £499.99. The £240 premium is substantial enough to compare the actual controls before reading either chair’s comfort claims.
Last verified: 7 October 2026. Both prices refer to the Black chair listings, before a separate code.
The comparison that matters at your desk
| Published detail | S100 | S300 | Decision to make |
|---|---|---|---|
| Lumbar layout | Dual dynamic lumbar support | Dual dynamic lumbar support with an adjustable 90°–105° support angle | Decide whether you need the additional control, rather than merely two pads |
| Armrest category | 4D coordinated | 6D adjustable | Check the extra positions against your desk and forearms |
| Seat-depth information | 16.53 inches, approximately 42 cm; a complete adjustment range is not listed in the text table | 40–47 cm | S300 offers the clearer published range for a seat-depth requirement |
| Seat-height information used here | Obtain the exact usable range before ordering | 47–55.5 cm | A lower price or shorter depth does not prove suitability for shorter legs |
| Maximum listed recline | 135° | 130° | S300’s premium is not an extra five degrees of recline |
| Recline/seat construction highlighted by Sihoo | S100’s standard recline design | Glass-fibre anti-gravity mechanism and four-spring seat suspension | Compare how the mechanism works, not just the angle number |
| Black UK listing | £259.99 | £499.99 | £240 difference |
Sources: S100 UK specification and S300 UK specification. The 42 cm value is a rounded unit conversion, not a separate measurement.
S300 earns its place when you need the seat range
A 40–47 cm published depth range gives a concrete reason to compare S300. If a fixed or insufficiently adjustable seat presses behind your knees, the ability to change depth matters more than the number of armrest directions.
The minimum seat height remains 47 cm. That is a separate fit constraint. A shorter user should check supported foot position as well as thigh clearance, using the S300 fit guide for users under 160 cm. A seat that shortens can still be too high for the intended setup.
For a shared desk, record the usable settings each person needs. A chair advertised for a broad height range is not proof that every user can achieve their own seat, arm and headrest position. The HSE workstation checklist provides a practical setup sequence without relying on a model’s marketing range.
S100 stays relevant when the basic layout fits
If you want dual moving lumbar sections, mesh and coordinated armrests, S100 already lists those features. Paying nearly twice its listed price for S300 needs an additional reason. The available UK text does not establish that S100’s mesh wears faster, that S300 prevents fatigue for a fixed number of hours, or that one treats a medical condition better.
Do not borrow S300’s “anti-gravity” mechanism description for S100 just because the names are close. Treat each current UK product’s specification section as its own source.
The C300 versus S300 guide offers another route if you are deciding between a lower-priced adaptive chair and S300. Buyers around £250 should also consider the B300 Pro versus C300 control comparison.
Practical questions
Does S100 really recline farther than S300?
The UK S100 page lists up to 135° and S300 lists up to 130°. Those numbers do not describe the resistance or feel of the mechanism. Use them to compare the published angle, not to infer the more comfortable recline.
Does S100 have the same seat slide as S300?
The current S100 text table gives a 16.53-inch depth rather than a complete adjustment range. Ask for the precise controls and range on the selected UK chair if a slider is essential. S300 explicitly publishes 40–47 cm.
Is S300 a better choice below 160 cm?
Not automatically. Its listed minimum seat height is 47 cm. Check whether you can support your feet, maintain thigh clearance and position the controls properly before choosing it for your height.
Is the £240 difference after a coupon?
No. It is £499.99 minus £259.99 using the selected Black listings before a separately applied code. Accepted discounts and delivered totals can change the gap.
Does the three-year warranty cover mesh that gradually stretches?
Sihoo’s policy covers manufacturing defects under normal use and excludes natural wear and tear. A claim depends on the cause and evidence, not just the fact that the component is mesh. Ask for the applicable part coverage before ordering.
Reference notes
Sources were checked on 7 October 2026. Manufacturer specifications and Desworthy’s arithmetic are kept separate from subjective sitting preferences. 16.53 inches × 2.54 = 41.9862 cm, rounded to approximately 42 cm. No fatigue curve or long-term wear result is inferred.
See the current S100 offer and S300 offer for the selected configurations and code conditions. For change-of-mind costs, read the after-sales policy before assembly.
Image credit: Sihoo, product photograph.
Note: This article is for reference only.