Beautyrest
Beautyrest Black® Series Three 15" Firm Mattress
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The honest verdict: the Series Three Firm is firm support at the upper tier. At about a 7 out of 10 it keeps your hips lifted and your spine level the way back and stomach sleepers need, with the Series Three upgrades a basic firm bed lacks: Self-Response™ Latex for a touch of responsive give, SurfaceTouch™ Gel for surface comfort, and Micro Diamond™ cooling so a firm surface stays cool. If you want genuinely firm Beautyrest Black with refined comfort and cooling, this is the one.
What it's made of, and what that does for you
- A firm 7/10 feel. Supportive and on-top (hips lifted, spine level) without the absolute hardness of an extra-firm bed.
- Self-Response™ Latex + SurfaceTouch™ Gel. A responsive latex layer and surface gel take the bare edge off the firmness without softening the support.
- Micro Diamond™ cooling + cool-to-the-touch cover. The Series Three cooling upgrade, which matters on a firm surface that sits you close to the materials.
- Triple-Stranded Pocketed Coil® core, 15 inches. Firm support and motion separation under the comfort layers.
- Premium Black build, 10-year warranty. Upper-tier firm with comfort and cooling a basic firm bed can't match.
What you notice lying on it
Lie down on your back and the support pushes back: your hips stay up, your spine settles level, and your lower back stays in contact with the surface instead of dropping into it. That is the firm-tuned Triple-Stranded Pocketed Coil® core. What keeps it from reading as hard is the layer above it, where the Self-Response™ Latex gives a quick, responsive push instead of a dead-flat board and the SurfaceTouch™ Gel takes the bare edge off where your shoulders and heels land. The cover feels cool to the touch the moment you set a hand on it.
Who it's for, and who it's not, said straight
This is built for back and stomach sleepers. On your back, the firm coil support holds your spine level; on your stomach, the firm feel keeps your hips from sagging and your lower back from arching over a night. And if you run warm on a firm bed, the Micro Diamond™ cooling targets exactly the heat a firm surface tends to hold.
- Side sleepers: a 7/10 firm will press on your shoulder; a medium or plush Black is the better fit.
- If you want the most accessible firm Black, the Series Two Firm delivers firm support a tier down.
- If you want the firmest possible feel, the Series Three Extra Firm goes harder, closer to an 8/10 with less give than this Firm.
Living with it over time
The partner factor is what you feel most over the years: those Triple-Stranded Pocketed Coils move independently, so when the person next to you rolls over or gets up, the motion barely crosses to your side. The pocketed-coil core also breathes more than all-foam, so the cooling has airflow to work with rather than trapped heat. And if you use an adjustable base, this mattress is built to work with one.
Why buy it from Mattress Overstock
Locally owned and serving Kentucky since 2012, with five showrooms you can actually walk into, in Lexington (on Nicholasville Road), Georgetown, Somerset, London, and Richmond. This is a bed you can come lie on in person before you commit, not just a picture on a screen, and no appointment is needed.
Whether an upper-tier firm sleeps cool and supportive, or just hard, is a lying-down question. Come feel the Series Three Firm beside the Series Two at any of the five Kentucky showrooms, and the team can walk you through the tiers side by side. You get a 100-day comfort guarantee; if it's not right, you exchange it for store credit toward any bed of equal or greater value. 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. Select your size to see the live Mattress Overstock price.
Compare the firm tiers in the full Beautyrest Black lineup.
What makes this mattress different
Upper-tier firm (7/10)
Firm coil support for back and stomach sleepers, with Series Three comfort and cooling a basic firm bed lacks.
Self-Response™ Latex + SurfaceTouch™ Gel
A responsive latex layer and surface gel take the bare edge off the firmness without softening support.
Micro Diamond™ cooling
Diamond foam and a cool-to-the-touch cover matter on a firm surface that sits you close to the materials.
Triple-Stranded Pocketed Coil® core, 10-year warranty
Firm support and motion separation under the Series Three comfort layers.
Firm support, with Series Three comfort and cooling
The Series Three Firm keeps the comfort layer measured so you sleep firmly on top of the support, with the Series Three upgrades a basic firm bed skips: Self-Response™ Latex, SurfaceTouch™ Gel, and Micro Diamond™ cooling. The firm-tuned Triple-Stranded Pocketed Coil® core keeps your spine level underneath.
For firm support a tier down, the Series Two Firm; for the firmest Series Three, the Extra Firm. See the firm tiers in 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.
Upper-tier firm for back and stomach sleepers
Back sleepers: firm coil support keeps the spine level, with more comfort and cooling than a basic firm bed.
Stomach sleepers: the firm feel keeps the hips from sagging and the lower back from arching.
Firm-bed people who run warm: Micro Diamond™ cooling targets the heat firm surfaces hold.
Probably not for you if you sleep on your side (a medium or plush suits better) or you want the firmest feel (the Extra Firm).
Specifications
| Height | 15" |
|---|---|
| Feel | Firm |
| 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 inches, firm. |
| 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 15" Firm?
About a 7 out of 10: genuinely firm and supportive, keeping you on top of the bed, with Series Three latex, gel, and Micro Diamond™ cooling so it doesn't sleep hard or hot.
How is it different from the Extra Firm?
The Series Three Extra Firm is an 8/10, firmer, with less give. This Firm (7/10) keeps strong support with a touch more responsive comfort.
Is it a hybrid?
Yes: Self-Response™ Latex, SurfaceTouch™ Gel, and Micro Diamond™ foam over a firm-tuned Triple-Stranded Pocketed Coil® support core.
How do delivery and the comfort guarantee work?
We deliver across Kentucky with our own team, usually next business day when your size is in stock, and we haul the old mattress away. You also get a 100-day comfort guarantee: if the feel isn't right, exchange it for store credit toward any bed of equal or greater value (no cash refund).
Can I see this mattress in person near me?
Yes, and with a mattress, we'd 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. We deliver free across our Kentucky service area and haul your old mattress away, and because everyone on our 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.
