Firmness
Extra Firm
Type
Pocket Spring
Depth (cm)
Number of Layers
Trial Period (nights)
60
Warranty (years)
Price Range
£149 to £279
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Man, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw here is a genuinely firm feel at a low price. Pocket springs move independently, which means less motion transfer than an open coil and support that follows your shape rather than fighting it. From £149 for a UK Single, it sits at the affordable end of the market without resorting to foam-only construction. Buying through Mattressman adds a 60-night trial and free next day delivery, so you're not locked in if the firmness turns out to be too much. The maker publishes little detail on depth or spring count, so you're trusting the feel more than the spec sheet. For back and front sleepers wanting firm support cheaply, that trade-off is reasonable.
Key Features & what's inside
Awaiting up to date specifications. Please check back later.
Who's it NOT for?
Skip this one if you're a lightweight side sleeper. A firm sleeping surface won't let your shoulder and hip sink in enough, which can mean pressure points and a sore morning. It's also not for anyone who wants a plush, cushioned top layer, or who needs detailed construction specs before buying.
Arthur Sleep Cool Rock Mattress
View all mattresses
How firm is the Arthur Sleep Cool Rock mattress?
The retailer listing describes it as having a firm sleeping surface. In practice that means minimal sink and a supportive, on-top-of-the-bed feel, which suits back and front sleepers and heavier builds. Lighter side sleepers may find it slightly too solid for comfortable pressure relief.
Does the Arthur Sleep Cool Rock come with a sleep trial?
Mattressman, the retailer currently listing it, offers a 60-night trial. That trial is Mattressman's own term rather than a manufacturer promise, so check the conditions at checkout and be aware it may not apply if you buy elsewhere in future.
What sizes does the Arthur Sleep Cool Rock come in?
It's available in UK Single, UK Double and UK King, priced from £149 to £279 depending on size. The Single starts at £149.00, which makes it one of the more affordable pocket spring options for a spare room or a child moving to a firmer bed.
How quickly can the Cool Rock mattress be delivered?
Mattressman lists free next day delivery, with a handling time of 0 to 1 days and transit of 1 to 3 days. Those are the retailer's own delivery terms, so timings depend on ordering through Mattressman and your location within the UK.
Is the Arthur Sleep Cool Rock any good?
Owner feedback on the Mattressman listing shows a 4.8 rating from 89 reviews, taken from the page's structured data. That's a strong score, although it comes from a single retailer. The mattress makes most sense if you specifically want a firm feel at a low price.
Couldn't find an answer to your question? Send us a message