Firmness
Medium Firm
Type
Hybrid
Depth (cm)
27
Number of Layers
3
Trial Period (nights)
100
Warranty (years)
5
Price Range
£699 to £1,189
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw here is temperature control. The top layer is 50mm of Kaymed's Smart Phase foam, which absorbs and releases body heat to keep the surface at a more even temperature, useful if you regularly wake up too warm. Beneath that, a reflex foam layer supports spinal alignment, and the pocket springs move independently to shape around your body, which means less disturbance from a restless partner. The medium to firm feel suits most back and combination sleepers. It isn't the cheapest hybrid around, but you're paying for a thermoregulating layer that many hybrids at this level simply don't have, plus a super stretch knitted cover and a foam encapsulated border for edge-to-edge use.
Key Features & what's inside
- Smart Phase Foam. A 50mm layer of Kaymed's exclusive Smart Phase foam, infused with microbeads, copper and phase change crystals. It thermoregulates by moving heat away from the mattress surface, absorbing and releasing body heat to keep you at a comfortable temperature.
- Reflex Foam Comfort Layer. A soft, flexible reflex foam that sits between you and the springs. It adds the support needed for good spinal alignment without a hard, boardy feel.
- Pocket Springs Support System. 1600 pocket springs, based on the kingsize mattress, each housed in its own fabric pocket. They react independently to movement through the night, which means the mattress shapes around your body rather than tilting you towards a partner.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
If you prefer a soft, sink-in feel, the medium to firm tension here will likely feel too solid, and lightweight side sleepers may not press far enough into the comfort layers. It's also fixed-cover rather than removable, so anyone who wants a washable cover should look elsewhere.
Kaymed Smart Phase 1600 Pocket Hybrid Mattress
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Is the Kaymed Smart Phase 1600 good for hot sleepers?
That's its main selling point. The top layer is Smart Phase foam infused with microbeads, copper and phase change crystals, designed to move heat away from the surface and absorb and release body heat. If overheating is your usual complaint with foam-topped mattresses, this layer is built to address it.
How firm is the Kaymed Smart Phase 1600?
Kaymed describes it as medium to firm. That suits most back sleepers and heavier side sleepers, though lighter people who sleep on their side may find it slightly too firm for comfortable shoulder and hip cushioning.
Does the Kaymed Smart Phase 1600 come with a trial?
Mattress Online lists a 100-night trial, but be aware this is the retailer's own offer, not Kaymed's, and it requires buying a mattress protector from them. If you purchase elsewhere, the trial terms may differ or not apply at all.
What guarantee does the Kaymed Smart Phase 1600 have?
It comes with a 5-year manufacturer's guarantee. According to the Mattress Online listing, an additional 5-year guarantee is available, with usage charges applying where applicable, so check the small print before relying on the full extended period.
How many springs does the Kaymed Smart Phase 1600 have?
It has 1600 pocket springs, based on the kingsize mattress. Each spring sits in its own fabric pocket and reacts independently, which means the mattress contours to your body and reduces motion transfer between partners.
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