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\n \n \n \n\n \n \n\n \n \n \n \n \n Price reduced from\n \n MSRP \n $874.00\n\n\n \n to\n \n \n \n \n \n \n \n \n Save 20%\n \n \n\n \n\n \n \n \n \n \n \n \n $699.00\n\n\n \n \n \n\n\n\n
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\n \n \n \n\n \n \n\n \n \n \n \n \n Price reduced from\n \n MSRP \n $874.00\n\n\n \n to\n \n \n \n \n \n \n \n \n Save 20%\n \n \n\n \n\n \n \n \n \n \n \n \n $699.00\n\n\n \n \n \n\n\n\n
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\n\n\n", "length": "75", "depth": "53", "sizeSelect": "Size: 53″ x 75″" }, { "id": "CalKing", "description": null, "displayValue": "Cal King", "value": "CalKing", "selected": false, "selectable": true, "url": "https://www.sleepworld.com/on/demandware.store/Sites-Sleepworld-Site/en_US/Product-Variation?dwvar_CAS-ONE-5M-FM-24-config_size=CalKing&pid=CAS-ONE-5M-FM-24-config&quantity=1", "price": { "sales": { "value": 1319, "currency": "USD", "formatted": "$1,319.00", "decimalPrice": "1319.00" }, "list": { "value": 1649, "currency": "USD", "formatted": "$1,649.00", "decimalPrice": "1649.00" }, "isSale": true, "percentDiscount": 20, "renderedPrice": "
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Casper One Firm Mattress 11\" Twin

The Casper One Firm Mattress 11\" is a firm, all-foam mattress built for back and stomach sleepers who want real spinal support without sacrificing comfort. It is Casper's signature three-layer foam construction, reimagined and refined over a decade of sleeper feedback. Every layer is engineered to breathe, so you stay comfortable through the night rather than waking up overheated and restless. If you want to feel the difference between this and every competing option in the same price range, stop by any Mancini's Sleepworld location and one of our sleep specialists will walk you through it side by side.

COMFORT AND FEEL: Firm feel with responsive foam and steady lumbar support that holds through the night.

SIZE: This twin sized mattress is a natural fit for solo sleepers, growing kids, and single adults in smaller bedrooms.

BEST SLEEP MATCH: Built for back and stomach sleepers who need a firm mattress for back pain relief. The surface pushes back with just enough give to keep hips and lower back aligned without letting them sink.

BEST FOR: Ideal for sleepers who need firm lumbar support, wake up with lower back tension, or tend to sleep hot through the night.

CONSTRUCTION SPECIFICATIONS: The top Breathe Flex Foam™ layer responds quickly when you shift positions and allows airflow to move through while you sleep. Align Memory Foam in the middle layer cradles pressure points along the hips and lower back. The Casper Core base is dense enough to keep this mattress from softening out after the first year.

SETUP AND COMPATIBILITY: Works with adjustable bases, platform frames, and slatted foundations. Arrives rolled and compressed, expands within hours, no tools needed.

NOT A FIT FOR: Side sleepers who need deep shoulder cushioning may find this firmness too unyielding. Not recommended for sleepers who strongly prefer a plush or pillow-top feel.

YOUR SLEEP, BACKED BY US

At Mancini's Sleepworld, every mattress purchase comes with the Rest Easy Promise. That includes our Best Price Guarantee, free next-day delivery with professional in-home setup, and flexible financing options. Your purchase is backed by a 120-night comfort guarantee from day one. Add a premium mattress protector at checkout and you can upgrade that to a full 365 nights. Come try this mattress in person at any of our locations before you decide.

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Casper One Firm Mattress 11\" Queen

The Casper One Firm Mattress 11\" is an all-foam mattress built for back and stomach sleepers who want reliable spinal support without the stiffness of a traditional firm bed. A firm mattress for back pain relief, the One layers three distinct foams in a straightforward stack that does exactly what it promises: keeps your body lifted, reduces pressure at the hips and lower back, and stays breathable from the first night. Every layer is built with all-night airflow in mind, so warmth never has a chance to build up underneath you. If you want to feel the difference between this and every competing option on the floor, stop by any Mancini's Sleepworld location and our sleep specialists will put this right next to them so you can decide for yourself.

COMFORT AND FEEL: Firm all-foam feel with a responsive surface and steady lumbar support underneath.

SIZE: This queen sized mattress is the go-to for solo back sleepers or couples who both prefer a firmer, more supportive feel.

BEST SLEEP MATCH: Back and stomach sleepers will feel most at home here. The firm mattress for back sleepers feel keeps the hips from dropping, so your lower back stays in a neutral position all night.

BEST FOR: Ideal for sleepers who need lower back support, prefer a responsive surface over dense memory foam, or wake up stiff from a mattress that lets them sink too deep.

CONSTRUCTION SPECIFICATIONS: Breathe Flex Foam® sits at the top, letting air move through an open-cell surface that responds quickly when you shift positions. Align Memory Foam sits beneath it, gently cradling the hips and shoulders without that slow, trapped feeling. The Casper Core base holds everything firm, resisting the compression that causes a mattress to soften and slope over time.

SETUP AND COMPATIBILITY: Arrives rolled and compressed in a box, expands within 24 hours, no tools needed. Compatible with adjustable bases, platform frames, and box springs.

NOT A FIT FOR: Side sleepers who need deep cushioning at the shoulder may find the firm feel too resistant. Those who prefer a plush, sink-in surface should consider a softer model.

YOUR SLEEP, BACKED BY US

Every mattress purchase at Mancini's Sleepworld comes with a 120-night comfort guarantee, and our sleep specialists are here before, during, and after the sale. Add a premium mattress protector at the time of purchase and extend your guarantee to a full 365 nights. We also back every purchase with our Best Price Guarantee, free next-day delivery, in-home professional setup, and flexible financing. Come try the Casper One in person at any Mancini's Sleepworld showroom before you decide. Our Rest Easy Promise means you never have to guess.

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Perfect balance of", "reviewBody": "Love it! Perfect balance of support and comfort.", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Kristina K." }, "datePublished": "2026-07-28", "name": "Best mattress and Amazing sleep!", "reviewBody": "Best mattress and Amazing sleep!", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Deborah T." }, "datePublished": "2026-07-27", "name": "Firm but comfortable. Gives good", "reviewBody": "Firm but comfortable. Gives good support.", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Kenneth B." }, "datePublished": "2026-07-26", "name": "Just what we needed.", "reviewBody": "Just what we needed.", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Kristin C." }, "datePublished": "2026-07-23", "name": "Lovely, soft bamboo sheets at", "reviewBody": "Lovely, soft bamboo sheets at a great value! Highly recommend.", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Ronald P." }, "datePublished": "2026-07-23", "name": "Very well constructed. High quality.", "reviewBody": "Very well constructed. High quality. Does have a discoloration in the fabric on top right side.\nWe are having a bit of discomfort sleeping . Aching shoulders and hips upon awakening. No cording on the sides to assist getting up (husband has had 9 prior back surgeries)", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "PATRICIA A." }, "datePublished": "2026-07-21", "name": "My daughter think is a", "reviewBody": "My daughter think is a little to soft", "reviewRating": { "@type": "Rating", "ratingValue": 3 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Peter H." }, "datePublished": "2026-07-18", "name": "Very happy with it", "reviewBody": "Very happy with it", "reviewRating": { "@type": "Rating", "ratingValue": 5 } }, { "@type": "Review", "author": { "@type": "Person", "name": "Robert B." }, "datePublished": "2026-07-17", "name": "Really enjoy this mattress it", "reviewBody": "Really enjoy this mattress it is the BEST i have ever had", "reviewRating": { "@type": "Rating", "ratingValue": 5 } } ] }, "PWRProduct": { "name": "Casper One Firm Mattress 11\"", "url": "https://www.sleepworld.com/casper-one--firm-mattress-11in/CAS-ONE-3M-FM-24.html", "description": "

Casper One Firm Mattress 11\" Twin

The Casper One Firm Mattress 11\" is a firm, all-foam mattress built for back and stomach sleepers who want real spinal support without sacrificing comfort. It is Casper's signature three-layer foam construction, reimagined and refined over a decade of sleeper feedback. Every layer is engineered to breathe, so you stay comfortable through the night rather than waking up overheated and restless. If you want to feel the difference between this and every competing option in the same price range, stop by any Mancini's Sleepworld location and one of our sleep specialists will walk you through it side by side.

COMFORT AND FEEL: Firm feel with responsive foam and steady lumbar support that holds through the night.

SIZE: This twin sized mattress is a natural fit for solo sleepers, growing kids, and single adults in smaller bedrooms.

BEST SLEEP MATCH: Built for back and stomach sleepers who need a firm mattress for back pain relief. The surface pushes back with just enough give to keep hips and lower back aligned without letting them sink.

BEST FOR: Ideal for sleepers who need firm lumbar support, wake up with lower back tension, or tend to sleep hot through the night.

CONSTRUCTION SPECIFICATIONS: The top Breathe Flex Foam™ layer responds quickly when you shift positions and allows airflow to move through while you sleep. Align Memory Foam in the middle layer cradles pressure points along the hips and lower back. The Casper Core base is dense enough to keep this mattress from softening out after the first year.

SETUP AND COMPATIBILITY: Works with adjustable bases, platform frames, and slatted foundations. Arrives rolled and compressed, expands within hours, no tools needed.

NOT A FIT FOR: Side sleepers who need deep shoulder cushioning may find this firmness too unyielding. Not recommended for sleepers who strongly prefer a plush or pillow-top feel.

YOUR SLEEP, BACKED BY US

At Mancini's Sleepworld, every mattress purchase comes with the Rest Easy Promise. That includes our Best Price Guarantee, free next-day delivery with professional in-home setup, and flexible financing options. Your purchase is backed by a 120-night comfort guarantee from day one. Add a premium mattress protector at checkout and you can upgrade that to a full 365 nights. Come try this mattress in person at any of our locations before you decide.

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Why this Mattress?

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  • \n Firm back support keeps your spine lifted all night\n
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  • \n Breathe Flex Foam™ adds bounce without trapping heat\n
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Casper One Firm Mattress 11"

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\n \n \n \n\n \n \n\n \n \n \n \n \n Price reduced from\n \n MSRP \n $874.00\n\n\n \n to\n \n \n \n \n \n \n \n \n Save 20%\n \n \n\n \n\n \n \n \n \n \n \n \n $699.00\n\n\n \n \n \n\n\n\n
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\n", "productUrl": "/casper-one--firm-mattress-11in/CAS-ONE-3M-FM-24.html" }