Available 
Bodyshape Vitality Bamboo Memory Mattress
from £189-£289.
£189-£289
Sizes tracked: Single, Small Double, Double, King Size, Super King
MattressOnline Mattress
Rock Hard Ultra Firm Mattress review
Rock Hard Ultra Firm Mattress is a value-led extra-firm foam mattress with a 100-night comfort trial, UK handcrafting and five size options.
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Last verified: 2026-09-04
Quick verdict
Rock Hard Ultra Firm Mattress is the clearer fit if you want a very firm, support-first feel rather than a cushioned one. With prices from £269 to £529, a 100-night comfort trial and a 3-year guarantee, it looks like a budget-conscious way to buy into the extra-firm category. Check the current size availability, because the Double was shown as out of stock at the time checked.
Available sizes and prices
Rock Hard Ultra Firm Mattress is listed with 5 size options from £269-£529. The visible sizes include Single, Small Double, Double, King Size, so use the table to compare the option that matches the exact size, colour, format or specification you want. Always confirm the final checkout price, delivery charge and stock status on the retailer page.
Key product details
These are the retailer details worth checking first for Rock Hard Ultra Firm Mattress: Brand: MattressOnline; Type: Mattress; Firmness: Firm; Sizes tracked: Single, Small Double, Double, King Size, Super King. Treat them as a quick fact sheet, then use the retailer page to verify any installation, warranty, delivery or model-number details before buying.
| Brand | MattressOnline |
|---|---|
| Type | Mattress |
| Firmness | Firm |
| Sizes tracked | Single, Small Double, Double, King Size, Super King |
| Price range | £269-£529 |
| Owner rating signal | 4.6 out of 5 shown; review volume needs checking with the retailer |
| Last checked | 2026-09-04 |
What the product page says
MattressOnline lists Rock Hard Ultra Firm Mattress as Firm, while the product copy also describes it as Extra Firm. The build is shown as reflex foam for both the support system and comfort layer, with ortho PU foam mentioned in the description, and the mattress is listed at about 25cm deep. It is handcrafted in the UK and tracked in Single, Small Double, Double, King Size and Super King.
What matters most from the listing
The key takeaway is that Rock Hard Ultra Firm Mattress is a MattressOnline foam mattress built around reflex foam and described as Firm or Extra Firm, depending on the retailer wording. That makes it a support-first option rather than a plush one, and the 25cm depth plus five tracked sizes — Single, Small Double, Double, King Size and Super King — give you useful practical flexibility. Independent third-party evidence for this exact model is limited, so the safest read is to weigh the spec, the £269-£529 price range and the 100-night comfort trial together.
Buyer trade-offs to weigh
The main trade-off is firmness versus cushioning: Rock Hard Ultra Firm Mattress may feel reassuringly stable, but that same feel can be too uncompromising for anyone who wants more give. The 100-night comfort trial reduces the risk of buying online, yet it still does not replace knowing your preferred feel. Before ordering, also check delivery cost, any removal service charges and whether the 25cm profile works with your frame, sheets and topper plans.
Price and value benchmark
At £269 for a Single and £529 for a Super King, this sits below the median price of comparable mattresses in the current set, which makes it look value-led rather than premium. The price jumps are straightforward: Single £269, Small Double £369, Double £369, King Size £469 and Super King £529. If you are comparing it with similar firm mattresses, the main question is whether the extra-firm feel and trial are worth more to you than a softer or more layered build at a similar checkout total.
How it compares with nearby alternatives
Compared with nearby options such as Emma Original Mattress, Classic Gold Mattress, European and Sealy Advantage Memory Essential Mattress, Rock Hard Ultra Firm Mattress sits in a firmer, simpler foam-led lane. The 25cm depth is useful to compare against alternative mattresses if you need low-profile clearance for a bed frame or a fitted sheet with extra depth. It also has five tracked sizes, which is broader than some lower-priced alternatives and helps if you are matching feel to room size rather than buying one standard footprint.
How much weight to give the reviews
The visible product rating is 4.6/5 from 39 reviews, which is encouraging but still a modest sample for a specific mattress model. MattressOnline’s wider retailer reputation is strong, but that reflects the shop overall rather than this exact mattress’s long-term performance. Treat the 4.6/5 on the product page as a useful confidence check, and keep the retailer-wide Trustpilot reputation separate from evidence about this specific mattress.
Who it suits
Rock Hard Ultra Firm Mattress should suit firmness-focused shoppers who want a simple foam mattress and do not want a cushioned or sinky feel. It also looks sensible for buyers who like the security of a 100-night comfort trial, want a 3-year guarantee and need size flexibility across Single through Super King. If you are comparing value as well as feel, the sub-£529 range keeps it in reach for shoppers who want extra-firm support without moving into a higher price band.
Who should look elsewhere
If you want more pressure relief, a plush top or a softer landing on the shoulder, this MattressOnline model is unlikely to be the right starting point. Side sleepers who prefer more cushioning may want to compare other foam, hybrid or pillow-top options before deciding, especially if they are looking at models above the £269 entry price. It may also be a poor fit if you are expecting premium cooling claims, because the available product information does not clearly support that kind of performance promise.
Comfort and support in everyday use
The foam construction on Rock Hard Ultra Firm Mattress points to a direct, support-first feel rather than a springy or deeply cushioned one. At 25cm deep, it is substantial enough to check against your bed frame, fitted sheets and topper plans, especially if you are choosing between the Single, Double or Super King variants. That can be a plus if you want a more stable surface, but it also means the mattress may feel quite uncompromising compared with medium-feel or comfort-layer-heavy alternatives.
Value check
On value, Rock Hard Ultra Firm Mattress makes most sense if the specification matches your preferred feel, because the price only works well when very firm support is what you actually want. The 100-night comfort trial and 3-year guarantee make the offer easier to consider online, but they should sit alongside the real questions: does the firmness suit you, does the depth fit your setup and is the final checkout total still competitive after delivery or removal costs? If those boxes are ticked, this looks like a sensible budget-led extra-firm option.
Good alternatives to compare
The closest alternatives to compare with Rock Hard Ultra Firm Mattress include Bodyshape Vitality Bamboo Memory Mattress, Sealy Advantage Memory Essential Mattress, Classic Gold Mattress. Use these cards to check whether a nearby model gives you a better price, a more suitable specification or a clearer match for your space and budget.
Available 
Sealy Advantage Memory Essential Mattress
from £299-£559.
£299-£559
Sizes tracked: Single, Small Double, Double, King Size, Super King
Available 
Classic Gold Mattress
from £159-£275.
£159-£275
Sizes tracked: Small Single, Single, Small Double, Double, King Size
Retailer details used
Last checked 2026-09-04. The source list below is included to help you check the details behind the comparison. Always confirm the latest price, delivery cost, stock status and product details with the retailer before buying.
More mattresses to compare
These related guides and reviews can help you compare nearby options before buying.
Questions about this mattress
Is Rock Hard Ultra Firm Mattress a good choice if I want a very firm feel?
Yes, it is one of the clearest fits in this set for shoppers who want extra-firm support rather than cushioning. MattressOnline lists it as Firm and also describes it as Extra Firm, so it is worth comparing against other firm models if you want a similar feel.
How does the price vary by size, and which size is best value?
The tracked prices are Single £269, Small Double £369, Double £369, King Size £469 and Super King £529. Best value depends on room size and budget, but the small double and double are priced the same here, so the better value is whichever size fits your space and sleeping setup.
What does the reflex foam construction mean for comfort and support?
The product page says the support system and comfort layer both use reflex foam, with ortho PU foam also mentioned in the description. In practical terms, that usually points to a simpler, support-first feel, so it is more about a firmer surface than a deeply cushioned comfort build.
Will the 25cm depth work with my bed frame and fitted sheets?
Probably, but it is worth checking before you buy. A 25cm mattress can affect headboard clearance, fitted-sheet depth and topper compatibility, so compare the retailer’s depth with your frame and bedding rather than assuming it will sit exactly like your current mattress.
Does the 100-night comfort trial make it safer to buy online?
It helps reduce the risk of ordering a very firm mattress sight unseen, because you have a chance to judge the feel at home. It does not remove the need to check the return conditions, whether the trial applies in your location and whether the mattress truly matches the firmness you want.