Beautyrest
Beautyrest Black® Series Three 15.25" Firm Hybrid Mattress
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The honest verdict: the Series Three Firm Hybrid is a true 7 out of 10 firm, built on a firm-tuned Triple-Stranded Pocketed Coil® core and topped with the latex, gel, and Micro Diamond™ cooling that set Series Three apart. It runs neck and neck with the standard Series Three Firm, so the honest move is to lie on both. Either way you get genuinely firm support for back and stomach sleepers, refined by responsive latex and kept cool by the Series Three layer.
A firm bed that does not sleep hard
Most firm mattresses force a trade: you get the support, you give up the surface. This one keeps the 7/10 backbone and softens only the top inch you actually touch, so hips lift and the spine stays level without the board-hard feel.
- A firm 7/10 feel. Hips lifted, spine level: supportive and on-top, without extra-firm hardness.
- Self-Response™ Latex + SurfaceTouch™ Gel. Responsive latex and surface gel refine the firm surface without softening the support underneath.
- Micro Diamond™ cooling + cool-to-the-touch cover. The Series Three cooling, which matters most on a firm surface you feel directly.
- Triple-Stranded Pocketed Coil® core, 15.25 inches. Firm support and real motion separation.
- Premium Black build, CertiPUR-US foams, 10-year limited warranty. Refined firm support meant to hold its shape.
Series Three is the Series Two build plus responsive pressure relief and added support, so on a firm surface the latex push-back and the Micro Diamond™ cooling count for more here than on a plush model.
What you notice the first few minutes lying on it
On your back, your hips come up to meet your shoulders and your lower back is supported instead of dropping into a hammock. On your stomach, the firm surface holds your midsection level. Press a hand in and the latex returns it quickly rather than letting you sink, and if you run warm, the cover stays cool where a softer bed builds up heat.
Who it is not for, and the Mattress Overstock team would rather say so now
- Side sleepers. A 7/10 firm will press on your shoulder and hip; a medium or plush Black is the better fit, because side sleeping needs the surface to give at those pressure points. Try the Series Three Plush Hybrid or Series Three Medium instead.
- Deciding against the standard Series Three Firm? They are close: the standard Series Three Firm is the same feel; lie on both and let your body choose.
- If you want the firmest feel. The Series Three Extra Firm goes harder.
Where it sits in the Series Three line
The firm tier is a short ladder: the Series Three Extra Firm sits at the rigid end, while this Firm Hybrid and the standard Series Three Firm share the same feel one rung down, with refinements a basic firm innerspring lacks. Coming off a builder-grade firm bed that went hard and hot, this is the same supportive backbone with a far more refined surface on top.
Living with it over time
Firm support tends to age well for the back and stomach sleepers it suits. If you share the bed, the Triple-Stranded Pocketed Coil® core earns its keep: each coil moves on its own, so a partner shifting or climbing out barely crosses to your side. It is compatible with an adjustable base, and the foams are CertiPUR-US certified.
Why buy it from Mattress Overstock
Locally owned and serving Kentucky since 2012, with five showrooms you can walk into, in Lexington (on Nicholasville Road), Georgetown, Somerset, London, and Richmond. No appointment needed. Choosing between two close firm models is a lying-down decision, so come feel the Series Three firms side by side, then select your size to see the live Mattress Overstock price. You also get a 100-day comfort guarantee: if it is not right, exchange it for store credit toward any bed of equal or greater value (pay the difference). No cash refund, but no restocking-fee games either. Free local delivery, free setup, and the team hauls your old mattress away. And no one on the floor earns more for steering you up a tier, so the guidance is honest.
Compare the firm options in the full Beautyrest Black lineup.
What makes this mattress different
A true 7/10 firm
Genuinely firm support that lifts the hips and keeps the spine level, without the board-hard feel of an extra-firm bed.
Self-Response™ Latex + SurfaceTouch™ Gel
Responsive latex and a surface gel layer refine the firm top without softening the support beneath it.
Micro Diamond™ cooling cover
Micro Diamond™ memory foam and a cool-to-the-touch cover pull heat off the surface, which counts most on a firm bed you feel directly.
Triple-Stranded Pocketed Coil® core
A firm-tuned coil core gives the support, and each coil moves on its own for strong motion separation between partners.
15.25-inch hybrid profile
A substantial Series Three hybrid build; measure it against your frame and deep-pocket sheets before delivery.
CertiPUR-US foams, 10-year warranty
Foams are CertiPUR-US certified for content and emissions, backed by a 10-year limited warranty on a premium Black build.
Adjustable-base compatible
Works on an adjustable base, so you can raise the head or feet without affecting the firm support.
Firm support, Series Three refinement, hybrid build
The Series Three Firm Hybrid is the Series Two build plus responsive pressure relief and added support, layered from the top down so a firm core never reads as harsh.
- Cool-to-the-touch cover. Pulls heat off the surface on contact, the cooling you notice first on a firm bed.
- SurfaceTouch™ Gel. A surface gel layer that softens the very top inch you press into, without giving up support.
- Self-Response™ Latex. Responsive latex that pushes back quickly and refines the firm feel rather than letting you sink in.
- Micro Diamond™ memory foam. Diamond-infused foam that helps move heat away from the sleep surface.
- Firm-tuned Triple-Stranded Pocketed Coil® core. The 15.25-inch coil core that does the supporting; each coil moves on its own for motion separation.
Note the 2K Micro Coils that headline Series Three live in the pillow-top models, not this hybrid; here the refinement comes from the latex, gel, and Micro Diamond™ cooling. It is a close sibling to the standard Series Three Firm, so the best way to choose is to lie on both. For the firmest Series Three, see the Extra Firm, and for the full set of firm tiers, the Beautyrest Black lineup.
Shop the Beautyrest Black lineup →What's inside Beautyrest Black
Five layers, engineered together: a cool quilted surface, pressure-relieving gel foam, and the Triple-Stranded Pocketed Coil® core that defines the Black line.
Refined firm for back and stomach sleepers
Back sleepers. This is the sweet spot. The firm coil core keeps your spine level and your hips from dropping, while the latex and gel keep the surface from feeling like a plank.
Stomach sleepers. A strong fit. The firm 7/10 surface holds your midsection up so your lower back does not arch through the night.
Firm-bed sleepers who run warm. The cool-to-the-touch cover and Micro Diamond™ foam target surface heat, which matters more on a firm bed you lie directly against.
Couples. The Triple-Stranded Pocketed Coil® core moves coil by coil, so a partner shifting or getting up barely reaches your side.
Heavier back and stomach sleepers. A firm hybrid core tends to hold support better than all-foam for higher body weights, keeping you on top of the bed rather than sinking in.
Probably not for you if you sleep on your side (a 7/10 will press your shoulder and hip; try the Plush Hybrid or Medium), or you want the hardest possible surface (the Extra Firm).
Specifications
| Height | 15.25" |
|---|---|
| Feel | Firm Hybrid |
| Firmness | 7 out of 10 (10 = firmest) |
| Construction | Cool-to-the-touch cover and SurfaceTouch™ Gel over Self-Response™ Latex, Micro Diamond™ foam, and a firm-tuned Triple-Stranded Pocketed Coil® core: 15.25 inches, firm hybrid. |
| Cooling | Series Three cooling: Micro Diamond™ memory foam and a cool-to-the-touch cover pull heat off the surface, over a Triple-Stranded Pocketed Coil core that breathes more than all-foam. |
| Motion isolation | Excellent: Triple-Stranded Pocketed Coils move independently, so a partner's movement barely crosses the bed. |
| Adjustable base | Yes, compatible with adjustable bases |
| Certifications | CertiPUR-US certified foams |
| Warranty | 10-year limited warranty |
| Trial period | 100 days at Mattress Overstock |
Frequently asked questions
How firm is the Series Three Firm Hybrid?
About a 7 out of 10, where 10 is the firmest: genuinely firm and supportive, in the Series Three hybrid build with latex, gel, and Micro Diamond™ cooling so it does not sleep hard or hot.
How is it different from the standard Series Three Firm?
They are close, the same firm feel in the Series Three line. The standard Series Three Firm is the sibling; lie on both to choose, since this is a lying-down decision.
Is this a good mattress for back and stomach sleepers?
Yes. The firm 7/10 surface keeps the spine level for back sleepers and holds the hips up for stomach sleepers, which is exactly what those positions need to avoid waking up sore.
Is it good for side sleepers?
Usually not. A 7/10 firm presses on the shoulder and hip, where side sleeping needs the surface to give. A medium or plush Black is the better call: the Series Three Plush Hybrid or Series Three Medium.
Does it have the 2K Micro Coils?
No. Series Three's 2K Micro Coils are in the pillow-top models. This hybrid gets the Self-Response™ Latex, SurfaceTouch™ Gel, and Micro Diamond™ cooling instead.
Does it sleep hot?
It is built to resist it on a firm surface: a cool-to-the-touch cover and Micro Diamond™ memory foam pull heat off the top, over a coil core that breathes more than all-foam. No mattress is a substitute for air conditioning, but firm hot-sleepers tend to do well on it.
How good is motion isolation for couples?
Strong. The Triple-Stranded Pocketed Coil® core flexes coil by coil rather than as one unit, so a partner rolling over or climbing out barely carries across the bed.
Can I use it on an adjustable base?
Yes, it is compatible with an adjustable base. Raising the head or feet does not change the firm support the coil core provides.
What is the warranty, and are the foams certified?
It carries a 10-year limited warranty on a premium Black build, and the foams are CertiPUR-US certified for content, emissions, and durability.
Can I see this mattress in person near me?
Yes, and with a mattress we would always rather you did. Mattress Overstock is a Kentucky-owned company that has served the state since 2012, with five showrooms you can visit: Lexington (on Nicholasville Road), Georgetown, Somerset, London, and Richmond. Come lie on this exact mattress in your own sleeping position before you decide. Delivery is free across the Kentucky service area and the team hauls your old mattress away, and because everyone on the floor is paid the same no matter which brand you choose, the guidance you get is honest.
Buy it from people you can actually visit
- Free local delivery To your home across Central & Eastern Kentucky.
- Free setup We place and set up your new bed in the room.
- Free old-mattress haul-away The old one goes out the same day the new one comes in.
Independently owned in Kentucky since 2012. Walk in any day (no appointment) and someone who actually knows the floor will help you find the right fit.
Still deciding?
Try it in person at any Kentucky showroom
Walk into any Mattress Overstock location, lie down, and feel the difference yourself. No appointment, no pressure. Our team has over 100 years of combined mattress experience and we're here to help you find the right fit.
