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90-day refund / replacement
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
Availability:
20 left in stock
Arrives
Tuesday, Nov 10
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At a glance
- Condition
- New
- Color
- Grey
- Size
- California King
- Set
- 12" Medium Firm
- Model
- OA12CK
- Dimensions
- 84 x 72 x 12 in
- Top Style
- Euro Top
Features 5
- Luxury Hotel-Level Cool Sleeping ExperienceThe Onlylucky california king mattress boasts a deluxe elevated Euro-top and refined 4-layer build with premium memory foam and reinforced independent pocket springs. Covered with skin-friendly, fiberglass-free 3D knit fabric, it delivers cloud-like comfort for luxury hotel-level rest. Built-in gel memory foam keeps you cool all night, while pocket spring systems and egg crate foam layers lift airflow by 30% for breathable, cozy rest for hot sleepers.
- Pain Relief & Spine AlignmentOnlylucky cal king mattress features multi-layer memory foam and reinforced responsive individual pocket springs for balance between comfort and stability. Its ergonomic 7-zone targeted support system evenly distributes body weight, fully fits to your body curves and optimizes spinal alignment, delivering soft cushioning for shoulders/hips while boosting lumbar support to ease pressure points. Suitable for all sleeping positions, it eases back and waist soreness.
- Superior Edge Support StructureOnlylucky cal king mattress 12 inch adopts 2.3mm perimeter edge springs and high-density support foam to reinforce the sides, maintain edge shape and avoid sagging. It effectively prevents body rolling, expands sleep space, reduces the risk of slipping off during bedtime movement and improves convenience when sitting, lying down, and getting in or out of bed. The upgraded edge design also protects the internal structure and extends the lifespan of the mattress.
- Effective Motion Isolation & Silent SleepOnlylucky california king hybrid mattress is equipped with 1000+ premium silent individual pocket springs and slow rebound memory foam. It absorbs noise and cushions vibration caused by tossing and turning. Excellent motion isolation minimizes motion transfer and effectively prevents sleep disruption. You can sink into steady, undisturbed deep sleep effortlessly, making it an ideal choice for light sleepers to enjoy peaceful rest all night long.
- CertiPUR-US Safety & 365-Night TrialOnlylucky california king mattress in a box comes vacuum-sealed for easy transportation. For optimal comfort, please allow 24 to 72 hours for the mattress to fully expand. It fits most standard bed frames and is suitable for bedrooms, guest rooms, hotels and dorms, equipped with practical side handles for easy movement and positioning. Onlylucky cali king mattress is CertiPUR-US certified, we offer a 365-night trial and 24-hour customer assistance.
Description
With years of sleep expertise, we prioritize comfort over cost. Built to global standards from user insights, our mattresses win global trust. Backed by years of expertise, we provide strict quality checks and 24/7 support for hassle-free buying and trials. Drawing on long-term industry know-how, we study varied sleep habits and keep refining mattresses to fit diverse home sleep demands.
Specs 32
| Brand | Onlylucky |
|---|---|
| Size | California King |
| Product Dimensions | 84"L x 72"W x 12"Th |
| Item Firmness Description | Medium Firm |
| Top Style | Euro Top |
| Cover Material | Polycotton |
| Number of Layers | 8 |
| Fill Material | Gel Memory Foam, High Density Foam, Memory Foam |
| Weight Limit | 1000 pounds |
| Special Feature | Breathable, Fire Retardant, Low Motion Transfer, Pressure Relief, Temperature Regulating |
| Weight Capacity Maximum | 1000 pounds |
| Additional Features | Breathable, Fire Retardant, Low Motion Transfer, Pressure Relief, Temperature Regulating |
| Mattress Coil Type | Pocketed Coil |
| Construction Type | Hybrid |
| Number of Mattress Coils | 1000 |
| Item Dimensions L x W x Thickness | 84"L x 72"W x 12"Th |
| Item Thickness | 12 inches |
| Item Depth | 12 inches |
| Item Dimensions | 84 x 72 x 12 inches |
| Mattress Comfort Layer Material | Gel Memory Foam, Memory foam |
| Material Type | 1000+ Individual Pocket Springs, Gel Foam, Memory Foam, Polycotton |
| Item Highlight | Gel Memory Foam & Pocket Springs, 7-Zone Deep Sleep, Targeted Lumbar/Hip Support, Pressure & Back Pain Relief, Medium Firm |
| Brand Name | Onlylucky |
| Product Benefits | Back Pain Relief, Improves Sleep, Posture Support, Pressure Relief, Reduces Toss & Turn |
| Model Number | OA12CK |
| Number of Items | 1 |
| Manufacturer | Onlylucky |
| Unit Count | 1 Count |
| Age Range Description | ALL |
| Set Name | 12" Medium Firm |
| Color | Grey |
| Style Name | Modern |
No specs match.
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Tuesday, Nov 10
Yes, absolutely! You may return this product for a full refund within 90 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Learn more about financing & leasing here.
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Queen mattress
Great mattress. Would definatly purchase again! Great support. No odor. Delivered on time.
Reviewed in the United States on August 2, 2026 by brenda saul
do it
Color: Grey
Size: King (U.S. Standard)
Set name: 14" Medium Firm
worth every penny
Reviewed in the United States on August 29, 2026 by geoff wood
Good buy.
Great for your back. At first it felt a little firmer than I expected, probably because I was used to a pillow top. Could use slightly more cushioning in my opinion—I like a mattress that hugs, but I’m enjoying great sleep.
Reviewed in the United States on December 24, 2025 by Disappointed
Firm/supportive Mattress
Color: Grey
Size: Queen (U.S. Standard)
Set name: 16" Medium Firm
After a card accident 5 years ago and a very bad dipping old mattress this is the perfect supportive quality needed and was finally given relief my back was begging for. It is definitely firm but once you relax into the bed it feels amazing. One thing I hate about boxed mattress is the smell and I was pleasantly surprised no smell. Overall a great find. The firmness is delivered, it’s definitely thicker than my older one but the topper is nice and comforting and the designs itself is cute. I don’t get warm and the material is comfortable not harsh on the skin. I do wish they offered darker colors but that’s just a preference I let it sit before use 48 hours and the unpacking was easy! It is a rather heavy mattress so some help might be needed for moving around.
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Reviewed in the United States on August 8, 2026 by Beeboop
Yes! Great Mattress!!
Really nice!!! The box is heavy so really needed two people but I managed getting in by myself. The mattress is really nice and thick. Be careful.opening it because it pops out very fast into a full sized mattress. It knocked me over. We'll worth it and would buy again.
Reviewed in the United States on May 14, 2026 by sleepy
Wonderfully Comfortable!! Get it !!
LOVE this mattress!! Crazy how a $400 mattress can be SO GREAT!! And now it's even less!!! I was suffering from major lower back pain from an old mattress. I started looking at new mattresses locally and I could not find one for under $1500. Paying for kids college tuition, the budget is tight and I did not want to go in to debt for a mattress. I asked friends and most recommended the hybrid mattresses. I started researching, found this one with great reviews and took a chance on it. Immediate back pain relief and so comfy!! I was worried about the firmness, it isn't too firm or too soft, it is perfection. Not sure how long it will last, but for right now it is perfect, and the price is right. If you are on the fence, try this one, you will be pleasantly surprised. You don't need to spend thousands on a mattress!!
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Reviewed in the United States on November 14, 2025 by Darlene McCormick
No support around the sides?
Color: Grey
Size: Queen (U.S. Standard)
Set name: 16" Medium Firm
So, this was my first "bed in a box" experience. The mattress was easy to assemble. I allowed it to "inflate" or "expand" fully for 72 hours. I ordered a "firm" mattress, and this one is very firm (in the center} which I like. My only "complaint" is there is absolutely no support around the edges of the mattress. You absolutely CAN NOT sit on the edge of the bed before getting on board. I do not understand WHY there are no strong coils around the sides to support body weight? Once you are on top, it is good, nice and firm. For the price it was OK, but I will definitely pay closer attention on my next purchase.
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Reviewed in the United States on August 1, 2026 by rochardin
Recomendados para persona que surrender de espalda baja.
Color: Grey
Size: Queen (U.S. Standard)
Set name: 16" Medium Firm
Lo recomiedo sufria dolor de espalda baja desde que lo compre el dolor se a desaparesido lo recomiendo es una buena inversion.
Reviewed in the United States on August 22, 2026 by Jose