Sleepeezee ActivFlex Response 1600 Memory Super King Mattress
The Sleepeezee ActivFlex Response 1600 is a firm hybrid that pairs 1600 barrel-shaped pocket springs with memory-style foams, which means you get precise, targeted support with a gentle cushioned surface on top.
- Firm support with a softer top
- Cooling gel helps regulate temperature
- Hypoallergenic & vegan-friendly
£1,149
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Sleepeezee ActivFlex Response 1600 Memory Mattress
More available sizes
Mattress details
Mattress
Sleepeezee ActivFlex Response 1600 Memory Mattress
Size
Firmness
Firm
Construction
Hybrid
Memory Foam
Depth (cm)
25
Layers
5
Layer Details
Soft Knitted Cover
A highly breathable knitted cover that's soft to the touch. It gives the mattress a genuinely luxurious finish.
Pillow Top / Comfort Layer
A soft polyester comfort layer that adds gentle cushioning, which means the surface feels welcoming rather than hard. It does this without compromising the firm feel underneath.
Staycool™ Gel
A deep layer of Staycool Gel that provides a consistently cooling sensation, helping to regulate your temperature. If you're a hot sleeper, this is the layer doing the work for you.
ActivFlex™ Spring Foam
A layer of spring foam that behaves like pocket springs for precise support, yet moulds to your body like foam. The result is support at every point of contact rather than pressure in a few places.
Pocket Springs Core
A core of up to 1600 barrel-shaped pocket springs delivering targeted support to key areas of your body. This is where the firm feel comes from.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- 90cm of width each: Two people get 90cm apiece, which means a partner who turns over frequently becomes background noise rather than a nightly disturbance.
- Firm support across the full width: The 1600 barrel-shaped pocket springs deliver the same targeted support at the edges as the centre, useful when two adults and a child end up spread across it.
- Pocket springs limit motion transfer: Individually moving springs respond only where weight lands, and at this width there's enough distance between sleepers for movement to fade before it reaches you.
- Staycool Gel across a bigger surface: Two warm sleepers put out more heat than one, and the cooling gel layer helps the larger sleeping area stay temperate through the night.
- Room for the whole household: When children or a large dog treat your bed as theirs, the extra 30cm over a UK king is often the difference between coping and comfort.
This size suits you if...
You share every night and find even a king leaves you aware of each other's movements, you have children or pets who regularly join you and want everyone to keep a fair share, or you have a large master bedroom where a smaller bed would look lost. Allow at least 3m x 2.9m of floor space so you can still move around it comfortably.
Consider another size if...
Your bedroom is smaller than the 3m x 2.9m we suggest, or you'd struggle to get a 180cm-wide mattress up the stairs. We'd recommend the UK king instead, which is 30cm narrower and the same length; allow at least 2.7m x 2.9m for it.
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FAQ's
Is the super king Sleepeezee ActivFlex Response 1600 good for restless partners?
It's one of the better pairings for this problem. The pocket spring core only compresses where weight is applied, so movement doesn't travel far, and the super king's 90cm per person adds physical distance on top. Firm mattresses also tend to transmit less wobble than soft ones, so a fidgety sleeper next to you is easier to ignore.
What room size do I need for the ActivFlex Response 1600 in a UK super king?
The mattress itself is 180 x 200cm, and we suggest a room of at least 3m x 2.9m. That leaves enough space to walk around the bed and open drawers without shuffling sideways. If your room falls short of that, the UK king is 30cm narrower and the same length, and we suggest at least 2.7m x 2.9m for it.
Is the super king ActivFlex Response 1600 a good choice for sharing with children?
Yes, with a caveat. The width means a child arriving at 3am doesn't force either adult to the edge, and the firm springs support everyone evenly wherever they end up. The caveat is the firmness itself: it's a supportive surface rather than a soft, sink-in one, which most families find works fine but is worth knowing before you buy.
How much space does each person get on a super king ActivFlex Response 1600?
Two people sharing get 90cm of width each. On a firm mattress like this one, that space matters, because you feel the surface more when you're pressed towards the middle of a smaller bed. With this much room, each of you can settle into your own sleeping position without negotiating territory.
Should I choose the ActivFlex Response 1600 in a UK king or super king?
If your room comfortably clears 3m x 2.9m and you share the bed, the UK super king is the safer pick: the UK king is 30cm narrower, and that difference is what you notice with a restless partner or visiting children. If space or access is tight, the UK king still gives a couple a sensible amount of room. Compare the retailers listed on this page for current pricing on both.