Spring King Ruby Ortho Extra Firm Single 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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Spring King Ruby Ortho Extra Firm Mattress
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Mattress details
Mattress
Spring King Ruby Ortho Extra Firm Mattress
Size
Firmness
Extra Firm
Construction
Orthopaedic
Open Coil Spring
Depth (cm)
27
Layers
3
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.
Key benefits
- Leaves room for a desk and wardrobe: At 90cm wide, the UK single keeps floor space free in a small bedroom, and we suggest allowing at least 2.1m x 2.8m.
- Motion transfer stops being a problem: Open coil units tend to move as one, which bothers couples, but with only one sleeper on a UK single there is nobody to disturb.
- Even support for back and front sleepers: The continuous coil lattice spreads support across the surface, which means a teenager or adult lying on their back or front stays level rather than sinking.
- Separate beds for guests who aren't a couple: A spare room fitted with two UK singles lets friends or siblings visiting each have their own firm bed instead of sharing one.
- Breathes well in a snug room: The Belgian damask cover lets air move away from your body, helpful in a small bedroom or loft conversion that tends to hold warmth.
This size suits you if...
You sleep alone on your back or front and have always liked a genuinely hard bed, or you're kitting out a compact room, such as a teenager's bedroom or a spare room that also works as an office.
Consider another size if...
You're an adult who sprawls across the bed or often has someone staying over. We'd recommend the UK small double instead: it is 30cm wider, and we suggest at least 2.4m x 2.8m for the UK small double.
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FAQ's
Will the Spring King Ruby Ortho single fit a mid sleeper or bunk bed?
The 90 x 190cm footprint matches standard UK single frames, so width and length are rarely the issue. Depth is the thing to check: the Ruby Ortho is 27cm deep, and raised frames often set a maximum mattress depth so the guardrail stays high enough. Check the frame maker's guidance before buying.
Is an extra firm single mattress suitable for a child?
It depends on how they sleep. Many children are light and sleep on their side, and they will likely find the Ruby Ortho too unyielding at the shoulders and hips. A child or teenager who sleeps on their back or front, or who already prefers a hard bed, is a much better match.
How much room do I need for a Ruby Ortho UK single?
We suggest allowing at least 2.1m x 2.8m of floor space for a UK single. At 3ft x 6ft 3in, it suits box rooms, and it fits loft conversions where only a narrow strip of floor sits under the sloping ceiling.
Is the Ruby Ortho single long enough for a tall teenager?
The UK single is 190cm long, the same length as the UK small double and UK double. If extra length matters, the UK king is 10cm longer, although it is also 60cm wider than the UK single and we suggest at least 2.7m x 2.9m for the UK king.
Ruby Ortho single or small double for one adult?
Both are the same length, but the UK single is 30cm narrower than the UK small double. If you lie still and your room is tight, the UK single is fine. If you spread out, the UK small double gives more width, and we suggest at least 2.4m x 2.8m for the UK small double.