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Zinus

Zinus 9 Inch Metal Smart Box Spring with Quick Assembly, King

  • Based on 4,048 reviews
Condition: New
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Availability: Only 5 left in stock, order soon!
Fulfilled by Kirk eCommerce LLC
Arrives Tuesday, Sep 29
Order within 10 hours and 21 minutes
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Size: King


Style: New/upgraded with quick assembly


Features

  • Steel Interior Frame With Poly Jacquard
  • STRONG, DEPENDABLE, AND READY IN NO TIME - As if its ultra-durable steel structure and convenient packaging werent impressive enough, our original Smart BoxSpring has been given a quick-assembly upgrade
  • DURABLY ENGINEERED - Durable steel is used to construct the inside framework of this foundation; Twin/Twin XL sizes support a maximum weight capacity of 350 lbs, while all other sizes can support up to 700 lbs
  • EASIER THAN EVER ASSEMBLY - With fewer bolts and tool-free locking brackets for intuitive setup, assembly takes only minutes to complete
  • VERSATILE FIT - Compatible with all Zinus mattresses and bed frames; please confirm dimensions before using with non-Zinus products
  • WARRANTY INCLUDED - Included a 5-year limited warranty for the box spring only; a bed frame is required to support this foundation and is sold separately

Description

As the backbone for solid mattress support, a box spring that falls short can make or break your night’s sleep. We developed the Smart BoxSpring® with unbeatable durability and rock-solid stability to keep your mattress in shape for years to come. And our latest quick assembly version gives you total confidence when it comes to setup, requiring fewer bolts and ingeniously designed with easy to use, tool-free brackets. With our simple, step-by-step instructions on hand, you’ll have this foundation built and ready to use within minutes. Built with a strong and durable steel frame and a versatile poly jacquard cover that slips right on, the Smart BoxSpring® is the picture of dependability for any mattress. All packed in a compact shipping box with everything included, even our 5-year worry free warranty! Now that’s peace of mind you can sleep on.

Size: King


Material: Alloy Steel, Fabric


Product Dimensions: 78.7"L x 75.5"W x 9"H


Style: New/upgraded with quick assembly


Special Feature: Quick Assembly, Tool-Free Locking Brackets


Other Special Features of the Product: Quick Assembly, Tool-Free Locking Brackets


Included Components: Steel Frame, Cover


Brand Name: Zinus


Unit Count: 1 Count


Manufacturer: Zinus


UPC: 841550325423


Number of Items: 1


Global Trade Identification Number: 23


Item Highlight: Mattress Foundation with Fabric Outer Cover, Strong Metal Frame, Easy Assembly


Manufacturer Warranty Description: Worry-free 5 year limited warranty included.


Item Type Name: Box Spring


Model Number: ZU-ABS-9KS


Manufacturer Part Number: ZU-ABS-9KS


Set Name: King 9 inch


Assembly Instructions Description: Easy to follow, step-by-step instructions included


Style Name: New/upgraded with quick assembly


Color: Grey


Finish Types: Powder Coated


Furniture Finish: Gray


Form Factor: Rectangular


Shape: Rectangular


Compatible With Mattress Size: King


Maximum Weight Recommendation: 700 pounds


Size: King


Item Dimensions L x W x H: 78.7"L x 75.5"W x 9"H


Item Weight: 45.8 pounds


Item Depth: 9 inches


Item Dimensions: 78.7 x 75.5 x 9 inches


Material Type: Alloy Steel, Fabric


Product Care Instructions: Wipe with Damp Cloth


Headboard Material: Metal


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Sep 29

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Excellent!!
Size: California King Style: New/upgraded with quick assembly
I recently purchased the ZINUS 9 Inch Metal Smart Box Spring for my California King mattress, and I couldn't be happier with my decision. Here’s why this product deserves every bit of its five stars: **1. Quick and Easy Assembly:** The term "Quick Assembly" isn't just marketing talk. Within 15 minutes, I had this foundation fully assembled. The instructions were clear, and the design is ingeniously simple. No tools needed, which was a major plus for someone like me who is not particularly handy. **2. Durability and Support:** Made from strong metal, this box spring feels incredibly sturdy. There's no sagging, even with the weight of my mattress and two people sleeping on it. It provides excellent support, ensuring that our mattress maintains its shape and comfort over time. **3. Versatile Use:** It's not just for box spring mattresses; it works perfectly with memory foam, innerspring, and other mattress types. This versatility makes it a great choice regardless of what kind of mattress you have or might purchase in the future. **4. Quiet and Stable:** One of the things I appreciate most is how quiet it is. No creaking or squeaking, which is a common issue with some foundations. It remains stable, even when getting in and out of bed, which adds to the overall sleeping experience. **5. Aesthetically Pleasing:** The design is sleek and modern, adding a touch of elegance to the bedroom. It's not just functional; it looks good too, blending well with various bedroom décors. **Conclusion:** The ZINUS 9 Inch Metal Smart Box Spring is an outstanding investment for anyone looking to enhance their sleeping environment. It combines ease of use, durability, and style in a package that delivers excellent value for money. I recommend this to anyone who wants to upgrade their bed setup without the hassle. A truly smart choice for a smarter sleep! ... show more
Reviewed in the United States on October 9, 2024 by slobobdan
    • Worth the purchase! Fast assembly and well made!
Size: Queen Style: New/upgraded with quick assembly
10/10! Easy to assemble! Took me 15 minutes! Sturdy and well made! Provided tools that made it even faster! Fit the bed frame perfectly. My son’s room is coming together quickly! Perfect height and width! Highly recommend! Mattress stores quoted me $180-200 for a queen box spring! So glad I found this online ... show more
Reviewed in the United States on June 29, 2026 by Kyrston Avery
    • No complaints
Size: Full Style: New/upgraded with quick assembly
The instructions were easy to follow, its fits my full size bed, none of the parts were missing and it was easy to assemble. Definitely buying another
Reviewed in the United States on June 29, 2026 by Shanna-Lee Battist
    • Easy to Assemble, Inexpensive, but May Only Last a Few Years
Size: Full Style: New/upgraded with quick assembly
This is the second ZINUS box spring that we have bought. We got the first one around 2017, and it lasted until 2022, so, not bad for an inexpensive easy to setup bed frame, but I notice that the 2022 version's metal is pretty soft, the metal indented in places when I tightened-down the screws that hold it together, and I don't think that should happen if the metal is quality. After 5 years of use, the last one somehow ended up bending breaking down and 2 of the support pieces broke off where they were welded together. I don't know if that happened after around 5 years of various house guests sleeping on the box spring, because I read that it can only support up to 350 lbs., and we used it for house guests in our Guest Room, so sometimes couples slept in it, and 2 people can weigh over 350 lbs. Bottom-line, it's super easy to put together, it's super inexpensive, it's relatively light-weight for one person to move around, but it's made of soft metal that may or may not last you more than 5 years, depending on the weight of whoever sleeps on it. We'll probably not buy it again if/when this one breaks down from use. ... show more
Reviewed in the United States on November 3, 2022 by Seattleite
    • Easy 45 Minute Assembly with sticky notes
Size: King Style: New/upgraded with quick assembly
I knew there were going to be a lot of parts, so I decided to be as organized as possible. After opening the box, I marked each group of items with a sticky note to make assembly as easy as possible. It took 45 minutes total to label, assemble, and put the cover on. I especially loved the mini ratchet tool that was included; it made tightening everything much faster and easier than using a standard allen wrench. Everything fit as expected and was easy to move into our rolling adjustment frame. The King mattress fits nicely on the metal box spring and does not slide around at all. It looks great and feels very solid. We are looking forward to having family visit and hope they enjoy the comfort. If you take the time to organize the pieces first and use the provided ratchet, this is a very straightforward and high-quality setup ... show more
Reviewed in the United States on January 5, 2026 by LivingLife
    • Good upgrade over wood
Size: Full Style: New/upgraded with quick assembly
Upgraded an old broken down wood box spring with this metal one from Zinus. Setup was just a few minutes, and done with 1 person. Seems very sturdy, I have a larger full size mattress on top as well, and have not noticed any flexing or noise after months of use. I appreciate the fact it is metal, and will probably last longer than the standard wood box springs. My only complaint would be the top is open, so when you go to tuck in sheets under the mattress, your hand will slip in there, but super small complaint. Still 5 star item for me, because the material is good and the price is right. ... show more
Reviewed in the United States on March 8, 2026 by Shopaholic
    • Disappointed: Broken and missing parts!
Size: King Style: New/upgraded with quick assembly
A little disappointed. I ordered this Friday night, and the product was promptly delivered the very next day early evening. Kudos to fast delivery! Yay! It’s 4:05 am and I’ve just built my new king size bed frame and I was in the process unpacking this supposed great box frame for king size mattress. As I am separating the pieces in alphabetical order A-S per the parts listing. I found part C had been built incorrectly where it was missing a push in button connection and missing 3 welds. A little concerning being that it suppose to support a king size bed and 2 bodies on top. With so many positive reviews and with so many purchases, I was expecting a great product. I hope it’s a just a one off situation and I'm the only unlucky one. But I am very disappointed at the fact that I won’t be sleeping on my new bed. Going back to the spot welds, it’s pretty janky at best. I can’t imagine this product lasting but as I said, with the many thousands of reviews and purchases by others, who knows. But I expected more. I’m not a welder so what do I know. Anyways… it’s just upsetting to get this delivered along with a purchase of new bed frame and this item was suppose to be the thing that brought it all together. And now, as I write this review, I’m stuck with parts scattered in my room and not a bed to sleep on. Also, because I ordered this product on the weekend I’m having to wait a couple days before getting this issue is resolved since customer service is not available till Monday. Im not saying I don’t recommend this product but I guess we’ll see how customer service handles the issue and how fast I get my part. I will update with a better review once this matter is resolved and I’m able to actually review the product in better conditions. ... show more
Reviewed in the United States on May 11, 2025 by Alexander Dubin
    • Strong, Sturdy, and Easy to Assemble!
Size: Queen Style: New/upgraded with quick assembly
The ZINUS 9 Inch Metal Smart Box Spring has been an excellent addition to our bed setup! I was impressed by how easy the assembly process was—everything came neatly packaged with clear instructions, and I had it put together in under an hour without any hassle. The design is very smart and straightforward, making it much more convenient than traditional box springs. This box spring provides strong, sturdy support for our mattress, and it has noticeably improved the overall comfort of our bed. The metal frame feels very durable and solid, and I love that it doesn’t squeak or shift, even with movement during the night. It’s also lightweight enough to move around if needed, yet still very stable once in place. The 9-inch height is perfect—it gives our bed the lift we wanted without being too tall, and it works great with our existing bed frame. Another big plus is that the cover has a nice, clean look that blends seamlessly with our bedding. Overall, I highly recommend this ZINUS box spring for anyone looking for an affordable, high-quality foundation that’s easy to assemble and provides reliable support. It’s a great value for the price! ... show more
Reviewed in the United States on August 25, 2024 by Amanda Cruz

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