Eastman House
Standard Profile 9" Box Spring Universal Flat Foundation
$259Queen
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Rock Extra Firm offers an extra-firm feel in a 12-inch innerspring mattress. It is a focused option for shoppers who prefer relatively little surface give and do not want to choose a taller mattress just to find a firmer feel.
An extra-firm innerspring feel without extra height.
The complete mattress height to include in your bed setup.
A surface intended for shoppers who prefer relatively little give.
The main comfort and support materials in this mattress.
Free setup and old mattress haul-away on orders $499+. Same-day delivery for $100 anywhere in LA when you order by 4pm.
Delivery details120 nights to be sure. One exchange for any mattress we stock, flat $100 swap fee. Check the full terms for eligibility and clearance exclusions.
Read the full termsThe Diamond Rock Extra Firm 12" Mattress offers an extra-firm feel in a 12-inch innerspring mattress. It is a focused option for shoppers who prefer relatively little surface give and do not want to choose a taller mattress just to find a firmer feel.
Try the Rock when ordinary firm mattresses still feel softer than you prefer. Compare comfort in every position you actually use, including your side if relevant. A brief test at the edge will not tell you how the surface feels after settling in across the full bed.
A higher firmness level is a comfort choice, not a guarantee of a better fit. Compare it in your normal sleep position before deciding that the firmest option is the right one.
The 12-inch profile leaves flexibility in your foundation choice. Measure your finished bed height and confirm the complete frame and base support requirements. Use our bed-height comparison to plan the mattress and foundation together. For an adjustable setup, confirm the exact mattress-and-base pairing before ordering.
Use the size selector for current options, pricing and availability. Check Los Angeles delivery and setup options, or contact an LA Mattress showroom for help comparing Rock Extra Firm with other feels. Compare more extra-firm mattresses if you are still building your shortlist.
Compare Queen-size options side by side. The differences that matter, in one table.
Swipe to compare all three mattresses →
| Queen | DiamondRock Extra Firm 12" Mattress | Tempur-PedicTEMPUR-ProAdapt® Medium Hybrid 12" Mattress | Stearns & FosterEstate® Firm 14.5" Mattress |
|---|---|---|---|
| Price (Queen) | $799 · was | $3,399 | $2,099 · was |
| Feel | Extra Firm | Medium | Firm |
| Best for | Shoppers specifically seeking an extra-firm innerspring | Most sleepers, thanks to the universal medium feel | Back and stomach sleepers |
| Cooling / cover | See product details | SmartClimate knit cover | TENCEL Fiber Cover |
| Height | 12″ | 12″ | 14.5″ |
| Warranty | See product details | 10 years | 10 years |
| Try in store | Check showroom availability | Check showroom availability | Check showroom availability |
| Shop Queen |
Protectors, pillows and bedding to complete your setup. Each item is optional and added only when you choose it.Bedding for Queen. Pillow sizes are shown separately.
Diamond Mattress is a 4th-generation family-owned company that has been handcrafting mattresses in Southern California since 1946. Founded by the Pennington family in Compton, California (now headquartered in Rancho Dominguez), Diamond is one of the few mattress manufacturers in America that is fully vertically integrated. They make their own pocketed coils, process their own memory foams, and cut and sew their own fabrics, all under one roof. This level of control over every component means Diamond can maintain strict quality standards that outsourced manufacturers cannot match. Every Diamond mattress is CertiPUR-US certified, GREENGUARD Gold certified for low chemical emissions, OEKO-TEX tested for harmful substances, and ECO INSTITUT certified for environmental safety. Diamond also uses REPREVE recycled fibers in select products, demonstrating their commitment to sustainable manufacturing practices.
Explore DiamondGet to know your mattress, from comfort and construction to delivery and care.
It has a extra firm feel, 9 out of 10 on our scale where 1 is the softest. It is a a weaker fit for side sleeping, great fit for back sleeping, and great fit for stomach sleeping.
From top to bottom it is built from Extra-firm comfort build, Comfort foams, and Innerspring core in a 12-inch profile. A surface intended for shoppers who prefer relatively little give.
It suits: Shoppers specifically seeking an extra-firm innerspring; Beds where the 12-inch profile suits the planned height; Sleepers comparing cushioning with spring support. It is a weaker fit for: Shoppers who want a deeply plush surface; Sleepers who prefer more surface give.
Yes, free white-glove delivery anywhere in Los Angeles on orders over $499, including setup and free haul-away of your old mattress. Order by 4pm for same-day delivery.
You have our 120-night comfort exchange. Sleep on it for at least 30 nights, and if it isn't right, exchange it for another mattress, we handle the pickup and redelivery.
Yes, 0% APR financing through Synchrony on approved credit, plus Acima lease-to-own with no credit needed. Most applicants are approved in minutes at checkout or in any showroom.
Yes, our Los Angeles showrooms in Koreatown, West LA, La Brea, Studio City, and Glendale carry our lineup on the floor. Walk-ins welcome, no appointment needed.
Prices for Queen · Choose options for other sizes
The underlying coil support system in this 12-inch mattress.
