Sleepeezee ActivFlex Response 3600 Memory Mattress
Mattress
Sleepeezee ActivFlex Response 3600 Memory Mattress
Size
Firmness
Construction
Depth (cm)
33
Layers
6
Layer Details
- Soft Knitted Cover. A highly breathable knitted cover that's soft to the touch. It gives the mattress a genuinely plush finish.
- Pillow Top with Mini Comfort Springs and Staycool Gel. An additional pillow layer containing up to 1000 mini comfort springs plus Staycool gel, which means the surface actively draws heat away from your body while you sleep. This is where much of the soft, cushioned first impression comes from.
- Soft Polyester Comfort Layers. Soft polyester layers that add full-body cushioning. They soften the transition between the pillow top and the layers below.
- ActivFlex Spring Foam. An innovative layer designed to mimic the precise support and movement of pocket springs while moulding to your body like a foam. In practice, that means contouring without feeling stuck in one position.
- Staycool Gel Layer. A dedicated gel layer that manages moisture within the mattress and aids temperature regulation. A sensible inclusion, since foam layers can otherwise trap warmth.
- Pocket Springs and Mini Comfort Springs Core. The core combines full-size traditional pocket springs with mini comfort springs, 3600 pocket springs in total. This gives targeted support to key areas of your body, so heavier zones like hips get more push-back.
Layer details from mattressnextday.co.uk product page, September 2026.
- 90cm each for two sharing: A soft pillow top surface is far more forgiving when you have 90cm each, so a partner shifting position happens at a comfortable distance.
- 3600 pocket springs across a wider bed: The full pocket spring core responds to each sleeper individually, which means movement on one side is less likely to travel across 180cm of width.
- Space for children and pets: If small visitors arrive in the night, the extra 30cm over a UK king often decides whether everyone actually sleeps.
- Cooling matters more when you share: Two bodies generate more warmth than one, and the Staycool gel in both the pillow top and its own dedicated layer helps manage that.
- Fills a large master properly: In a big bedroom or period property a smaller bed can look lost, and the 180 x 200cm footprint suits the scale of the room.
This size suits you if...
You share the bed every night and a restless partner keeps waking you, since distance does more for undisturbed sleep than any comfort layer can. Or children or a large dog regularly join you and a UK king has started to feel crowded. You'll also need the room for it: we suggest at least 3m x 2.9m, with something closer to 3.5m x 3.2m feeling comfortable.
Consider another size if...
Your bedroom falls short of the 3m x 2.9m we suggest as a minimum, or you sleep alone. The UK king is 30cm narrower at the same length and we'd recommend it instead; allow at least 2.7m x 2.9m for that size.
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Is the Sleepeezee ActivFlex Response 3600 in a UK super king good for restless partners?
It's one of the better matches. The 3600 pocket springs respond to each sleeper separately rather than as one surface, and with 90cm each for two people sharing, most movement simply happens too far away to wake you. The soft pillow top feel also means less rolling towards a heavier partner than you'd get on a single-piece foam slab.
What room size do I need for the ActivFlex Response 3600 super king?
We suggest at least 3m x 2.9m as a minimum, and around 3.5m x 3.2m feels right if you want bedside tables on both sides and space to walk around the bed. Measure door swing too: at 180 x 200cm this mattress takes up serious floor area, and a door opening into the room eats into it quickly.
How much bigger is the super king ActivFlex Response 3600 than the UK king?
The UK super king is 30cm wider than the UK king, and the two are the same length at 200cm. That extra width is the difference between 90cm each and noticeably less when a child or dog joins you. If your room can't stretch to it, the UK king needs at least 2.7m x 2.9m by our guidance.
Is the super king ActivFlex Response 3600 difficult to move upstairs?
It can be. At 180 x 200cm and 33cm deep with a built-in pillow top, this is a large, heavy item, and tight landing turns or narrow stairwells in older houses are the usual sticking point. Measure the route before ordering, including any turns, and check the retailer's delivery access requirements through the listings on this page.
Does the ActivFlex Response 3600 sleep cooler in a super king?
The cooling layers are the same in every size, but sharing changes the equation. Two people warm a bed faster than one, so the Staycool gel in the pillow top and the dedicated gel layer beneath have more work to do here. The 90cm each also helps, since you're less likely to be pressed against a second heat source all night.