Sealy PostureTech Oxwich Super King Mattress
The Sealy PostureTech Oxwich Mattress pairs twice-tempered PostureTech springs with a thin polyester fibre layer, which means you get firm, responsive support with only a light cushion on top.
- Extra-firm feel for back sleepers
- Responsive support at pressure points
- Reinforced edges against roll-off
£599
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Sealy PostureTech Oxwich Mattress
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Mattress details
Mattress
Sealy PostureTech Oxwich Mattress
Size
Firmness
Extra Firm
Construction
Depth (cm)
24
Layers
2
Layer Details
Polyester fibre layer
Super soft polyester fibres sit over the spring unit under a traditionally tufted damask cover. They add a light cushion to your movement, though the surface still feels firm.
PostureTech Core Support spring unit
Twice-tempered PostureTech springs form the foundation and give maximum support to pressure points, with EdgeGuard tucked inside. You get firm, responsive support and a reinforced edge against roll-off.
Layer details from crushedvelvetbedstore.co.uk product page, November 2026.
Key benefits
- Space from a restless partner: With 90cm each for two people sharing, a partner who turns over all night is simply further away, which matters on a surface this firm and lightly cushioned.
- Room when children climb in: When a small child arrives at 3am, a 6ft wide bed means the adults can still sleep in their own space rather than clinging to the sides.
- Fits a large dog as routine: If a big dog sleeps on the bed every night, the UK super king leaves both of you with a usable share of the mattress.
- A clear step up from the UK king: It is 30cm wider than the UK king at the same length, giving you 15cm more each, which you will notice on any night with company.
- Edges you can use: Sealy fits EdgeGuard reinforcement inside the spring unit, so on a bed this wide you can sleep near the side without feeling you might roll off.
- Turning is a two-person job: The Oxwich is double-sided and needs regular turning, and at 180 x 200cm you will want a second pair of hands each time.
This size suits you if...
You share the bed every night with a partner who moves a lot, or children and a large dog regularly join you, and you want an extra firm, flat surface with 90cm each for two people sharing.
Consider another size if...
Your bedroom is smaller than our suggested 3m x 2.9m, or you sleep alone. We'd recommend the UK king instead, and we suggest at least 2.7m x 2.9m for that size.
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FAQ's
What size bedroom do I need for a Sealy Oxwich super king?
We suggest at least 3m x 2.9m for a UK super king, with around 3.5m x 3.2m feeling comfortable once you add bedside tables and walking space. Check that the bedroom door can swing fully open with the bed in place, and that wardrobe doors and drawers still have room to open.
Is a UK super king big enough for two adults and a child?
It gives 90cm each for two people sharing, which leaves room for a young child to settle between you without anyone being pushed to the edge. Because the Oxwich is rated extra firm with only light cushioning, a small child lying on it will feel a flat, supportive surface rather than sinking into a dip.
How much bigger is the Oxwich super king than the king?
The UK super king is 30cm wider than the UK king, and the two are the same length. Shared between two people, that comes to 15cm more each. If your room is tight, we suggest at least 2.7m x 2.9m for the UK king, against at least 3m x 2.9m for the UK super king.
What bedding fits a Sealy Oxwich UK super king?
You need super king sheets and a 260 x 220cm duvet. The Oxwich is 24cm deep, so choose a fitted sheet with pockets deep enough for that depth. Bedding in this size usually costs more than king equivalents, so factor it in if you are replacing everything at once.
Will a super king Oxwich fit in a loft conversion bedroom?
Measure first. At 6ft x 6ft 6in, the UK super king needs a full-height wall for the headboard, so the slope of the ceiling often decides where the bed can go. Check the stair width, landing turns and the door to the room too, then compare the retailers listed on this page.