Sealy Advantage Topaz Natural Super King Mattress
The Sealy Advantage Topaz Natural is a medium-feel sprung mattress with wool fillings.
- Natural wool for a cushioned feel
- Support that holds up over years
- Medium feel suits most sleepers
£659
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Sealy Advantage Topaz Natural Mattress
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Mattress details
Mattress
Sealy Advantage Topaz Natural Mattress
Size
Firmness
Medium
Construction
Wool
Natural
Depth (cm)
27
Layers
3
Layer Details
Quilted Cover
The cover and fillings are stitched together into a patterned comfort quilt. This gives a settled, traditional surface rather than a loose, removable top.
Wool
A wool filling that adds a soft, cushioned feel. It suits sleepers who prefer natural materials and a classic sprung-mattress character.
PostureTech CS Springs
These springs respond to your body weight, targeting support at the areas where pressure is applied, which means your heavier zones get held up rather than sagging. They are twice tempered, so the steel is treated to stay resilient over time.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Distance beats any comfort layer: With 90cm each for two people sharing, a restless partner can turn over all night without their movement ever reaching your side.
- Room for midnight visitors: When a child pads in at 3am, or the dog treats the bed as home, everyone still gets a workable share of the 180cm width.
- Springs that support two different bodies: The PostureTech CS springs respond to whoever presses down where, which means each of you gets support matched to your own weight rather than a compromise.
- Edges you can actually use: EdgeGuard high-density foam runs round the sides, so the outer stretch of all that width is usable sleeping space rather than a soft roll-off zone.
- Fills a larger master properly: In a big bedroom or period property a UK king can look undersized; the extra 30cm of width here suits the room as well as the sleepers.
This size suits you if...
You share the bed every night and one of you sleeps restlessly, so distance matters more than any comfort layer. Or your household routinely ends up sharing, children wandering in or a large dog claiming a corner, and you want everyone to keep a share. Or your master bedroom is generous enough that a UK king would sit in it looking a little lost.
Consider another size if...
Your bedroom is under the 3m x 2.9m we suggest as a minimum, or you'd be squeezing past the bed to reach a wardrobe. We'd recommend the UK king instead: it's 30cm narrower, the same length, and needs at least 2.7m x 2.9m.
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FAQ's
Is the Sealy Advantage Topaz Natural super king big enough for two restless sleepers?
Yes, and this is the size we'd point restless couples towards. With 90cm each for two people sharing, most movement simply happens too far away to disturb you. The PostureTech CS springs also respond to body weight where it's applied, so a heavier partner pressing down on their side doesn't change how yours feels.
Will the Sealy Advantage Topaz Natural super king fit in my bedroom?
Allow at least 3m x 2.9m, which is our guidance rather than Sealy's, and around 3.5m x 3.2m feels comfortable. Measure with wardrobe doors open and check the bedroom door swing clears the footprint. At 180 x 200cm this size dominates a room, so if the numbers are tight, think carefully before committing.
Is the super king worth it over the UK king for this mattress?
If you share, usually yes. The UK super king is 30cm wider than the UK king and the same length, and that extra width is what turns a shared bed into genuinely undisturbed sleep. If your room is under our suggested 3m x 2.9m, though, the UK king (minimum 2.7m x 2.9m) is the sensible call.
Can children or pets share this size with us?
This is the size where occasional co-sleeping stops being a squeeze. At 180cm wide, a child climbing in at night or a large dog settling at the foot still leaves two adults with reasonable space, and the EdgeGuard foam sides mean whoever ends up on the outside edge is properly supported rather than perched.
Will a super king Sealy Advantage Topaz Natural get up the stairs?
It's a sprung mattress, so it can't be rolled or folded, and at 180cm wide the tricky points are tight landing turns and narrow doorways rather than the stairs themselves. Measure the awkward corners before ordering. On the plus side, at 27cm deep it's a manageable thickness to grip and manoeuvre.