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Firm
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On Sale
Overview
- SleepMatch: blue
Mancini's Sleepworld Onyx Firm Mattress 13"
- Built for firm support without sacrificing surface comfort
- Cooling stretch knit cover actively draws heat away
- Gel memory foam layer softens contact without going soft
- 840 pocketed coils move independently for clean support
- Dense upholstery-grade base resists wear for years
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In Stock
Overview
Mancini's Sleepworld Onyx Firm Mattress 13" Twin XL
The Mancini's Sleepworld Onyx Firm Mattress 13" is a pocketed coil innerspring mattress built for back sleepers and anyone searching for a firm mattress for back pain relief. At a full 13 inches, it layers gel-infused memory foam over high-density firm support foam so you get just enough give at the surface without losing the lift underneath. The coil system is fabric-wrapped, meaning each spring responds to you individually rather than dragging your whole body into one spot. Stop by any Mancini's Sleepworld location and a sleep specialist will lay this out next to every competing option so you can feel the difference yourself.
COMFORT AND FEEL: Firm feel with a cool, lightly cushioned surface and steady lumbar support beneath.
SIZE: This Twin XL sized mattress is a natural fit for taller solo sleepers, college students, or single adults in a guest room or studio.
BEST SLEEP MATCH: Best for back sleepers and stomach sleepers who want firm mattress support. The firm coil base keeps the spine level while the gel foam layer takes the edge off pressure at the hips and shoulders.
BEST FOR: Ideal for sleepers who run warm at night, need consistent spinal alignment, or wake up with lower back stiffness.
CONSTRUCTION SPECIFICATIONS: The heavyweight stretch knit cover is built to sleep cool from the first night. Gel-infused memory foam directly underneath takes pressure off contact points without letting you sink. Firm and extra-firm high-density foam layers above the coil system keep the feel honest and consistent. An 840-count fabric-wrapped pocketed coil core and a shock-absorbing base layer round out the build. Foams are CertiPUR-US certified.
SETUP AND COMPATIBILITY: Delivered flat with in-home professional setup available. Compatible with adjustable bases, platform frames, and box springs. No tools needed for setup.
NOT A FIT FOR: Not ideal for side sleepers who need deep pressure relief at the shoulder, or for anyone who prefers a plush or pillow-top feel.
YOUR SLEEP, BACKED BY US
Every mattress at Mancini's Sleepworld comes with a 120-night comfort guarantee and our Rest Easy Promise, which includes the Best Price Guarantee, free next-day delivery, and flexible financing. Add a premium mattress protector at the time of purchase and you can upgrade your guarantee to a full 365 nights. Come try this one in any of our stores before you buy, and let our sleep specialists help you land on the right choice.
Features
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Suitable For Adjustable Base
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Motion Separation
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Cooling Technology
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Edge Support
- SleepMatch: blue
Mancini's Sleepworld Onyx Firm Mattress 13"
Features
- SKU: BRK-ONY-3XM-FM-25
- MPN: 25WICRAFF_FP33XL
- GTIN: 810146419150
- Brand: Mancini's
- Collection: Sleepworld
- Type: Innerspring
- Mattress In A Box: No
- Firmness: Firm
- Height: 13
- Length: 80
- Width: 38
- Shipping Height: 13
- Shipping Width: 80
- Shipping Length: 38
- Warranty: 10 Year
- Cover Material: Polyester Knit
- Quilting Layers: 3/4 H.D Gel Infused M - Foam, 3/4 Extra Firm Quilt Poly
- Comfort Layers: 1'' Med-Firm H.D. Foam,1.5'' Extra Firm H.D. Support Foam
- Support System: 8'' 840 Pocketed coil ,1.0'' Shock Absorbing H.D. Base Foam
Specification
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Suitable For Adjustable Base: Yes
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Motion Separation: Yes
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Cooling Technology: Yes
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Edge Support: Yes