Sealy Advantage Quartz Memory Small Double Mattress
The Sealy Advantage Quartz Memory Mattress combines a MemorySense foam layer with PostureTech CS springs, which means you get that slow, cradling memory foam feel on top with proper spring support underneath rather than an all-foam base.
- Memory foam eases pressure points
- Stable edges, no roll-off feeling
- Twice-tempered springs hold their shape
£519
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Sealy Advantage Quartz Memory Mattress
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Mattress details
Mattress
Sealy Advantage Quartz Memory Mattress
Size
Firmness
Medium Firm
Construction
Foam
Memory Foam
Depth (cm)
27
Layers
4
Layer Details
Quilted Cover
The cover is stitched together with the fillings to create a patterned comfort quilt, which means the surface has a soft, cushioned feel built in rather than a flat top. It's the first thing you'll notice when you lie down.
MemorySense Foam
This memory foam layer adapts to your body position, cocooning you and easing pressure at the shoulders and hips. In practice, that means less tossing and turning to get comfortable.
PostureTech CS Springs
These springs respond to your body weight to give deep-down support, so heavier areas get more pushback than lighter ones. They're twice tempered, meaning the steel is heat-treated twice to stay resilient over years of use.
EdgeGuard
A high-density foam strip reinforces the springs around the perimeter, extending their lifespan. You'll feel this as a firmer, more supportive edge, useful if you sit on the bed or share it and need the full width.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Real room to spread out: At 120cm across, the UK small double is 30cm wider than the UK single, so a solo sleeper can shift position freely through the night.
- Fits compact double bedrooms: It's 15cm narrower than the UK double, which can be the difference between a door that clears the bed frame and one that doesn't.
- Usable to the very edge: EdgeGuard foam firms up the perimeter, which matters more at 4ft wide because there's less width to spare before you reach it.
- Works for occasional sharing: For a guest room used by visiting couples a few nights a year, this size shares comfortably without demanding the floor space a full double needs.
- Standard UK sizing: The 4ft small double is a stock UK size, so frames, fitted sheets and protectors are easy to find on the high street.
This size suits you if...
You sleep alone and want more width than a single without giving over the whole room to the bed, or you need a double bed for a box room, loft conversion or small second bedroom where every centimetre of floor counts. It also suits a guest room that hosts the occasional couple. Allow at least 2.4m x 2.8m of floor space for this size.
Consider another size if...
You share the bed every night, as 120cm is a squeeze for two adults long term. We'd recommend the UK double instead, which is 15cm wider and the same length; allow at least 2.6m x 2.8m for it.
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FAQ's
Is the Sealy Advantage Quartz in a UK small double big enough for a couple?
For occasional nights, yes. The firm EdgeGuard perimeter helps here, because two people on a 120cm mattress use the edges more than they would on a wider bed. For nightly sharing most couples find 4ft tight, and we'd suggest the UK double, which is 15cm wider at the same length.
Will the UK small double Sealy Advantage Quartz fit in a box room?
Often, and that's largely the point of this size. The mattress is 120 x 190cm, and we suggest a room of at least 2.4m x 2.8m so you can still open the door, get dressed and reach the bed from one side. Measure the room with furniture in place before ordering.
Is a small double better than a single for a teenager?
If the room can take it, usually yes. The UK small double gives 30cm more width than the UK single at the same 190cm length, which suits a teenager who has outgrown a single bed. The Medium Firm feel of this mattress works for a growing sleeper, though very light side sleepers may find it slightly firm.
What bed frame does the Sealy Advantage Quartz small double need?
Any standard UK small double frame or divan, sized for a 120 x 190cm mattress, sometimes labelled as 4ft. It's a common UK size, so you won't struggle to find one. Check the frame's internal dimensions match, because a 4ft 6in double frame will leave a visible gap around this mattress.
Does the small double feel different from the larger sizes of this mattress?
The construction is identical: the same MemorySense foam, PostureTech CS springs and 27cm depth appear in every size. What changes is width per sleeper. Solo, the UK small double feels generous; shared, you'll notice the EdgeGuard edge support more, since both sleepers sit closer to the perimeter than they would on a UK king.