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ZINUS

ZINUS 9 Inch WonderBox(TM) Smart Box Spring, Quick Assembly Mattress Foundation, Durable Metal Frame, King, Grey

  • Based on 18,652 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Tuesday, Sep 2
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Size: King


Style: 9 inch


Pattern Name: New Quick Assembly


Features

  • EASY DELIVERY & A CLEANER PLANET Delivered in our earth-friendly WonderBox that is surprisingly small and easy to maneuver through doorways and tight corners
  • EFFORTLESS ASSEMBLY: Tool-free design snaps together in minutes for a frustration-free setup
  • CUSTOMIZABLE COMFORT: Choose from two heights to create your perfect sleep oasis 5 inches for a lower profile, or 9 inches for an extra boost
  • DURABLE STEEL CONSTRUCTION: Provides long-lasting support for your mattress, maximizing comfort and lifespan
  • WORRY-FREE WARRANTY Sleep soundly with an included 5-year warranty. Box spring only, a bed frame or platform bed 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


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


Special Feature: Easy assembly, Squeak Resistant


Color: Grey


Finish Type: Unfinished


Size: ‎King


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


Special Feature: ‎Easy assembly, Squeak Resistant


Color: ‎Grey


Finish Type: ‎Unfinished


Included Components: ‎Box Spring, Instruction Sheet


Compatible With Mattress Size: ‎King


Brand: ‎ZINUS


Furniture Finish: ‎Gray


Assembly Required: ‎Yes


Manufacturer: ‎Zinus


UPC: ‎841550372724


Form Factor: ‎Rectangular bed frame


Global Trade Identification Number: ‎24


Item Weight: ‎36.7 pounds


Item model number: ‎ZU-FBSSG1OC-09K


Date First Available: April 28, 2024


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Sep 2

Yes, absolutely! You may return this product for a full refund within 100 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Perfect solution for box
Size: Full Style: 5 inch Pattern Name: New Quick Assembly
We got a new bed frame for my young teen son which required a box spring mattress. I was not looking forward to having another giant mattress to drag upstairs. This frame was the perfect solution at a great price. The delivery box wasn't too big (compared to a full-sized mattress), and it was pretty easy to put together in just a few minutes. It seems to be pretty sturdy. I also like that it came with a fabric cover, although, it did have a small tear which won't even be noticeable with the main mattress on top. ... show more
Reviewed in the United States on July 31, 2025 by RPowell
    • Effortless Assembly and Rock-Solid Support – A Huge Improvement Over Older Models
Size: California King Style: 7 inch Pattern Name: New Quick Assembly
I’m really impressed with how far assemble-at-home box springs have come. I bought this California King size box spring and couldn’t be happier with the experience. Setup was incredibly easy—everything fit together perfectly, and I had it fully assembled in under 30 minutes without any frustration. It feels solid and well-built, offering great support for the mattress. The last time I assembled a box spring at home was back in 2018, and that one was a struggle from start to finish. This one was the complete opposite—quick, intuitive, and sturdy. Highly recommend if you're looking for a hassle-free option that doesn't compromise on quality. ... show more
Reviewed in the United States on July 20, 2025 by Michael Accardi
    • Highly recommend. Sturdy
Size: King Style: 9 inch Pattern Name: New Quick Assembly
While easy to assemble the pictures in the instructions didn't fully explain how to put together. Very sturdy and would buy again as it is light enough and if moving you could take apart to avoid the hassle of trying to navigate through tight corners.
Reviewed in the United States on June 28, 2025 by Angela Jackson
    • First Impressions
Size: Full Style: 9 inch Pattern Name: New Quick Assembly
The Positives: -It was pretty simple to assemble (or would have been see cons). Just 6 screws. Straightforward instructions. Minimal parts to connect. -It feels solid with two adults and a child in it. -Not Noisy so far. Silent in fact. I was concerned about it being noisy so I added electrical tape at all metal to metal contact points. Particularly the end of the cross braces. This made things fit tighter and there shouldn't be any metal rubbing together now. Can't say this made the difference but it is quiet. -Price -The cover was easy to fit. It's basically just a fitted bed sheet. Cons: -No surprise, the metal is the typical cheap Chinese pot metal. -The machining for one of 6 screw holes was missing most of it's threads. This made it impossible to assemble using the screws provided. Thankfully I had a box of nuts and bolts and was able to complete the assembly without the screw. -Two of the cross braces didn't have the plastic grommet in the end of them. This would have meant extra metal to metal contact. I remedied this by fashioning my own grommet out of furniture foot pads. I shouldn't have needed to do this but I'm sure it will work better now anyway. Tip: Use electrical tape at all metal to metal contact points to avoid noisy metal to metal friction. This was at the end of cross braces and then the center contact point where 4 screws are connected. Summary: It was a very cheap solution that seems to solve the problem. If you don't have a little Macgyver ability you might want to avoid this. The quality of the material and machining matches the price. Ease of assembly with simple instructions is a plus. Will update if the thing falls apart. ... show more
Reviewed in the United States on December 9, 2024 by Beau
    • Squeak-Free w movement on matresss
Size: Queen Style: 5 inch Pattern Name: New Quick Assembly
Durable. Easy to put together. Doesn't squeak when getting in and out of bed or while moving around on bed. I'd recommend to anyone looking for a quick easy set up at affordable price
Reviewed in the United States on July 7, 2025 by Andrew Elmer
    • Terrible construction and won’t stay put together.
Size: Queen Style: 5 inch Pattern Name: New Quick Assembly
Review Image by Gillian Murphy Gillian Murphy
Review Image by Gillian Murphy Gillian Murphy
Review Image by Gillian Murphy Gillian Murphy
If I could give this zero stars I would. Not particularly easy to assemble since everything came unlabeled, the directions just a couple pictures, but I figured it out. Purchased it to make my new bed firmer which it did do! But it does slide around a bit, annoying but again no big deal, I would just slide it back in place and planned on putting down rubber strips or something to help it grip. The issue: Occasionally when rolling over I heard a pop and worried something was breaking and woke up today with the corner of my mattress sinking. I pulled the bed off and realized a lot of the slats had come loose and the bed was sinking inside the frame. The slats aren’t long enough to meet all the way inside their little holders and every time the frame shifts they pop out of place. The four outside sides aren’t screwed in so they can be pulled slightly apart and they just pop right out. Seems like it wouldn’t be a big deal, but since it slides around on my frame it keeps popping out. Also the plastic joints holding the two middle pieces together have a small plastic piece holding it on, so no matter how you place it the weight of the mattress slightly off the frame pops it out of place and that is also contributing to the issue with the slats. Seems dangerous and bad for your mattress. I’m super frustrated with how this turned out and now I’m going to have figure out how to disassemble the whole thing and return it somehow. See pictures for a better explanation. ... show more
Reviewed in the United States on May 22, 2025 by Gillian Murphy Gillian Murphy
    • Excellent Product
Size: Full Style: 5 inch Pattern Name: New Quick Assembly
Highly recommend this for a quick, durable and transportable box spring. It was so easy to assemble. We used for college kid moving and we were unable to transport a typical box spring due to size. Will be getting my other kid one too!!
Reviewed in the United States on July 15, 2025 by Tanya Simmer

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