Spring King Ruby Ortho Extra Firm Mattress
The Spring King Ruby Ortho Extra Firm is an orthopaedic open coil mattress at the firmest end of the scale.
- Extra-firm for back & front sleepers
- Even support with less sinking
- Breathable cover helps you stay cool
£239
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Beneath the Spring King Ruby Ortho Extra Firm's breathable Belgian damask cover sit soft polyester fibre fillings, then a traditional open coil unit made from one continuous high tensile spring, which means a firm, evenly supportive surface rather than a cradling one. At 27cm deep it has more presence than many budget orthopaedic options. It suits back and front sleepers who want genuinely firm support, although lightweight side sleepers will likely find it too unyielding. Available in five UK sizes from Single to Super King.
Mattress specifications
Firmness
Extra Firm
Type
Orthopaedic
Depth (cm)
27
Number of Layers
3
Trial Period (nights)
Warranty (years)
1
Price Range
£239 to £439
Best Sleeping Position(s)
Stomach Sleeping
Certifications
BS 7177
Assessed from Spring King's published specification for this mattress, captured September 2026, and from regular price comparison across our UK retail partners.
Why should you choose this mattress?
Choose the Ruby Ortho if you actively want an extra firm feel. That is a smaller group than the marketing for orthopaedic mattresses sometimes suggests, but if you sleep on your back or front, or you have simply always preferred a hard bed, this delivers it at a modest price. The continuous coil lattice spreads support across the whole surface, which means less of a sinking feeling when you change position. The Belgian damask cover is breathable, helpful if you tend to sleep warm, and the mattress is hypoallergenic and fire resistant to the BS7177: 2008 domestic standard. Delivery is free next day to mainland UK, though some addresses may incur a small fee. The guarantee is one year, which is short.
Key features & layer details
Cover
A breathable Belgian damask fabric cover. The breathability helps air move away from your body, which means you are less likely to overheat.
Comfort Fillings
Soft white fibre fillings made from 100% polyester. These add a little softness over the springs, though the overall feel remains extra firm.
Support System
A traditional open coil unit built from one continuous high tensile spring formed into a lattice. This spreads support evenly across the mattress, which means a stable, uniformly firm surface underneath you.
Layer details from mattressnextday.co.uk product page, September 2026.
Best suited for?
Back sleepers
The continuous high tensile coil lattice gives an evenly supportive, extra firm surface, which suits anyone who likes to lie flat on a hard bed.
Front sleepers
Extra firm support from the open coil unit keeps the surface flat and unyielding, which means you are less likely to sink in when lying face down.
Warm sleepers
The breathable Belgian damask cover helps air move away from your body, which means you are less likely to overheat during the night.
Allergy sufferers
The mattress is hypoallergenic, so it is a sensible pick for anyone who wants a bedding choice that suits sensitive sleepers.
Side sleepers, especially lighter ones, will probably find it too hard on the shoulders and hips. Anyone who prefers a contouring, pressure-relieving feel should look at pocket sprung or foam hybrid options instead. Couples wanting minimal motion transfer may also struggle, as open coil units tend to move as one.
Save on an earlier or ex-display model
Some retailers still sell the earlier version of this mattress, or ex-display and returned stock at a lower price. These are the sizes where it costs less than the current model's best price.
Spring King Ruby Ortho Extra Firm Mattress
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FAQ's
How firm is the Spring King Ruby Ortho mattress?
It is rated Extra Firm, the hardest end of the firmness scale. That suits back and front sleepers who want minimal sink, but it is a genuinely hard feel, so if you have never slept on an extra firm bed before, expect a noticeable adjustment period.
How deep is the Spring King Ruby Ortho Extra Firm?
It measures 27cm deep, so standard fitted sheets should fit without trouble.
What sizes does the Spring King Ruby Ortho come in?
Five UK sizes: Single, Small Double, Double, King and Super King.
Does the Spring King Ruby Ortho have a guarantee?
Yes, it comes with a one year guarantee. That is shorter than many brands offer, so factor it into your decision if long-term cover matters to you.
Is the Spring King Ruby Ortho hypoallergenic?
Yes, it is certified hypoallergenic, and it meets the BS7177: 2008 fire resistance standard for domestic use, classed as low hazard.
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