Firmness
Type
Open Coil Spring
Depth (cm)
27
Number of Layers
3
Trial Period (nights)
Warranty (years)
5
Price Range
£379 to £659
Best Sleeping Position(s)
Certifications
Assessed from the specification published by MattressNextDay, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw here is the pairing of responsive springs with natural wool. The PostureTech CS springs are twice tempered, which means the steel is treated for resilience, so the support should hold up over years of use rather than softening quickly. Wool above the springs gives that gentle, cushioned surface that people who dislike the sink of memory foam often prefer. EdgeGuard high-density foam runs around the sides, so you can sleep or sit near the edge without feeling you might roll off. The medium firmness suits most sleepers, although anyone wanting a distinctly firm or distinctly plush feel should look elsewhere. At £379 to £659 depending on size, it is honest value for a sprung, wool-filled build.
Key Features & what's inside
- 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.
Who's it NOT for?
If you want the contouring hug of memory foam, this wool-and-spring build will feel springier and more traditional than you are after. It is also not ideal if you need a distinctly firm or soft mattress, as this is a medium. And no sleep trial was listed, so cautious buyers may prefer a brand offering one.
Sealy Advantage Topaz Natural Mattress
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Is the Sealy Advantage Topaz Natural firm or soft?
It is a medium. That middle-ground feel suits most sleeping positions, giving back and combination sleepers balanced support, although lightweight side sleepers might prefer something a touch softer and heavier sleepers something firmer.
How deep is the Sealy Advantage Topaz Natural mattress?
It is 27cm deep, which means standard fitted sheets should go on without a struggle while still leaving room for the wool fillings and spring unit.
Does the Sealy Advantage Topaz Natural have a guarantee?
Yes, it comes with a 5-year guarantee from Sealy, as stated on the mattressnextday.co.uk listing. Sealy is also an NBF-Approved Manufacturer, an industry scheme covering how beds are made.
What sizes does the Sealy Advantage Topaz Natural come in?
Five UK sizes: Single, Small Double, Double, King and Super King. Prices run from £379 to £659 depending on the size you choose.
Is there a sleep trial with the Sealy Advantage Topaz Natural?
No trial period was listed on the mattressnextday.co.uk page we reviewed. If trying before committing matters to you, check the returns policy of your chosen retailer before ordering, as terms vary between shops.
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