Silentnight UltraGel 3000 Mirapocket Box Top Firmer Mattress
The Silentnight UltraGel 3000 Mirapocket Box Top Firmer is a firm hybrid with a softer story on top.
- Firm feel with a cushioned top
- Extra support under your hips
- Minimises partner disturbance
£955
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The Silentnight UltraGel 3000 Mirapocket Box Top Firmer has a pillow top and a layer of gel infused UltraGel foam over the spring system, which means you get supportive push-back underneath with a little cushioning where your body meets the mattress. The 3,000 pocket spring count is based on the kingsize, and the springs are zoned firmer through the centre third to help keep your spine aligned. At 35cm deep it's a substantial mattress. Handcrafted in the UK by a National Bed Federation approved, B-Corp certified brand, it suits sleepers who want firm support without a hard sleeping surface.
Mattress specifications
Firmness
Firm
Type
Hybrid
Depth (cm)
35
Number of Layers
4
Trial Period (nights)
100
Warranty (years)
5
Price Range
£715 to £1,365
Best Sleeping Position(s)
Back Sleeping
Stomach Sleeping
Certifications
BS 7177
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
Why should you choose this mattress?
If you need firm support but find truly firm mattresses uncomfortable, this design is a sensible middle path. The zoned Mirapocket springs are firmer in the centre third, which means extra support under your hips, the heaviest part of most sleepers. Above that, a layer of mini pocket springs works like bellows to move air through the comfort layers and reduce motion transfer, helpful if a partner tosses and turns. The UltraGel foam adapts to your shape and, per the listing, is five times more breathable than memory foam, so hot sleepers get some relief too. Yes, it's a chunky 35cm deep, but that depth is where the layered comfort comes from. Buying through Mattress Online, you get a 100-night trial and a 5 year guarantee.
Key features & layer details
Pillow top
An additional comfort layer sewn on top, which means a more luxurious, cushioned feel the moment you lie down. It softens the first impression of what is otherwise a firm mattress.
UltraGel
A gel infused foam layer that adapts to your shape and movements, distributing your weight evenly. According to the listing it's five times more breathable than memory foam, so it should hold less heat.
Mini Pocket Springs
A layer of 1,000 mini pocket springs that work like bellows, pushing air through the comfort layers as you move. They also help decrease motion transfer, so you feel less of a restless partner.
Mirapocket Springs
The main support unit of 2,000 Mirapocket springs, zoned so the centre third is firmer. That means greater support under your midsection and encouragement towards better spinal alignment.
Layer details from mattressonline.co.uk product page, September 2026.
Best suited for?
Couples
A layer of mini pocket springs works like bellows and helps decrease motion transfer, so you feel less of a restless partner moving about.
Warm sleepers
The UltraGel foam is described as five times more breathable than memory foam, which means it should hold less heat overnight.
Back sleepers
Zoned Mirapocket springs are firmer through the centre third, giving extra support under your midsection and encouraging better spinal alignment while you lie flat.
Heavier sleepers
Firm zoned springs under the hips give supportive push-back where most weight sits, while the 35cm depth adds layered comfort above.
Lightweight side sleepers may find the firm core a little unyielding, even with the pillow top. Owner feedback also flags the depth and weight as practical considerations: at 35cm it needs deep fitted sheets, and it's awkward to rotate or move on your own. If you prefer a soft, sink-in feel, this might not be the best choice.
Save on an earlier or ex-display model
Some retailers still sell the earlier version of this mattress, or ex-display and returned stock at a lower price. These are the sizes where it costs less than the current model's best price.
Silentnight UltraGel 3000 Mirapocket Box Top Firmer Mattress
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FAQ's
How firm is the Silentnight UltraGel 3000 Mirapocket Box Top?
It's rated firm. That said, the pillow top and UltraGel foam layer give the surface a softer, more cushioned feel than the firm core alone would suggest, so it suits sleepers who want solid support without lying on something hard.
How many springs does the UltraGel 3000 have?
The kingsize contains 3,000 pocket springs in total: 2,000 zoned Mirapocket springs in the main support unit plus 1,000 mini pocket springs in the comfort layers. Spring counts vary with mattress size, so smaller sizes will contain fewer.
Does the Silentnight UltraGel 3000 come with a trial period?
Mattress Online lists a 100-night trial on this mattress, along with a 5 year guarantee. These are the retailer's own terms, so check the conditions wherever you buy.
How deep is the UltraGel 3000 mattress?
It's 35cm deep, which is a substantial mattress. You'll likely need deep fitted sheets, and owner reviews mention the depth and weight make it harder to handle than a standard mattress.
Is the Silentnight UltraGel 3000 good for hot sleepers?
It has features aimed at cooler sleep. The UltraGel foam is described on the listing as five times more breathable than memory foam, and the mini pocket springs work like bellows to move air through the comfort layers.
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