Arthur Sleep Cool Rock Mattress

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. 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.

Back sleepers
The extra firm feel and pocket springs that follow your shape give a supportive, no-sink surface, which suits anyone lying mostly on their back.

Front sleepers
A firm surface keeps your hips from dropping into the mattress, which means a flatter, more level feel when you sleep face down.

Budget buyers
Described as good value for pocket springs, it gives a genuinely firm feel at the affordable end of the market without foam-only construction.

Couples
Independent pocket springs mean less motion transfer than an open coil, so one person turning over is less likely to disturb the other.

Heavier sleepers
Extra firm pocket springs resist sinking, which means a steady, supportive feel for bodies that press deeper into a softer mattress.

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.

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 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.

What sizes does the Arthur Sleep Cool Rock come in?

It's available in UK Single, UK Double and UK King. It's 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. The mattress makes most sense if you specifically want a firm feel at a low price.