Mattress Online Rock Hard Mega Firm 1500 Pocket King Size Mattress
The Rock Hard Mega Firm 1500 Pocket Mattress does exactly what the name suggests.
- Extra-firm for back & front sleepers
- Handcrafted in the UK, fully recyclable
- 100-night trial & 5-year guarantee
£434
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Mattress Online Rock Hard Mega Firm 1500 Pocket Mattress
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Mattress details
Mattress
Mattress Online Rock Hard Mega Firm 1500 Pocket Mattress
Size
Firmness
Firm
Construction
Pocket Spring
Orthopaedic
Depth (cm)
25
Layers
2
Layer Details
Comfort Layer
Soft white fibre fillings, finely filled with high density compressed polyester. This gives a thin layer of cushioning over the springs, which means you'll feel comfort at the surface but firmness underneath rather than a plush, sink-in feel.
Support System
1500 pocket springs that gently contour around your body for personalised support. Because each spring moves independently, you get support matched to your shape and less motion transfer if you share the bed.
Layer details from mattressonline.co.uk product page, September 2026.
Key benefits
- 75cm each for two people sharing: You each get 75cm of width, enough to settle into your own sleeping position without negotiating for space on a surface this firm.
- Less disturbance on different schedules: The 1500 pocket springs move independently, which means an early alarm and a quiet exit on one side transfers less movement to the other.
- 200cm of length for taller sleepers: The UK king is 10cm longer than the UK Double, a real difference if one of you is approaching six foot and used to feet hanging off the end.
- Steel piping keeps the edges usable: Edge support around the perimeter means the full 150cm width is genuinely sleepable, rather than a soft border you roll away from.
- Firm support across the whole width: Each spring pushes back where you're heavier, so both sleepers get the same solid feel whatever their build, without a dip forming in the middle.
This size suits you if...
You share the bed every night and a double now feels like a squeeze, especially on a firm surface where you can't sink out of each other's way. Or one of you is tall enough that the extra 10cm of length over a standard double is the real reason you're upgrading. It also suits couples on different schedules who want less disturbance when one gets up first.
Consider another size if...
Your bedroom falls short of the 2.7m x 2.9m we suggest for a UK king. In that case we'd recommend the UK double instead, which needs at least 2.6m x 2.8m and still suits two sharing.
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FAQ's
Is the Rock Hard Mega Firm 1500 in a UK king a good size for couples?
Yes, for most. The UK king gives 75cm each for two people sharing, which is 7.5cm more each than the UK double. On an extra-firm mattress that margin is welcome, because neither of you sinks in, so you stay more aware of each other. More width means fewer accidental nudges through the night.
How much room do I need for the Rock Hard Mega Firm in a UK king?
We suggest a bedroom of at least 2.7m x 2.9m for a UK king, and around 3.2m x 3.2m feels comfortable. New build master bedrooms can shrink quickly once wardrobes go in, so measure the floor you'll actually have left rather than trusting the floor plan.
Is the UK king Rock Hard Mega Firm long enough for tall sleepers?
At 200cm, the UK king Rock Hard Mega Firm is 10cm longer than the UK double version. If one of you is over six foot, that length is often the upgrade that matters, keeping feet on the mattress rather than over the edge. Firm support runs the full length, so nothing softens at the foot end.
Will I feel my partner getting up early on this mattress?
Less than on most. The 1500 pocket springs respond individually, so movement on one side doesn't travel far, and the firm build means less rolling toward a dip when someone leaves. Combined with 75cm each in the UK king, an early riser can slip out with minimal disturbance.
Should I get the Rock Hard Mega Firm in a king or super king?
The UK super king is 30cm wider, giving 90cm each for two sharing against the UK king's 75cm, and both are the same length. If a pet routinely claims part of the bed, that extra width helps. You'll need a room of at least 3m x 2.9m for the UK super king, so check your space first.