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Zinus

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

  • Based on 18,504 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Sunday, Jun 15
Order within 21 hours and 25 minutes
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Size: Twin


Style Name: 9 inch


Design: 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.

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: Twin


Product Dimensions: 73.8"L x 37.9"W x 9"H


Special Feature: Squeak Resistant, Easy assembly


Color: Grey


Finish Type: Painted


Size: ‎Twin


Product Dimensions: ‎73.8"L x 37.9"W x 9"H


Special Feature: ‎Squeak Resistant, Easy assembly


Color: ‎Grey


Finish Type: ‎Painted


Included Components: ‎Box Spring, Instruction Sheet


Compatible With Mattress Size: ‎Twin


Brand: ‎ZINUS


Furniture Finish: ‎Gray


Assembly Required: ‎Yes


Manufacturer: ‎Zinus


UPC: ‎841550372694


Form Factor: ‎Standard Box Spring


Global Trade Identification Number: ‎94


Item Weight: ‎20.3 pounds


Country of Origin: ‎China


Item model number: ‎ZU-FBSSG1OC-09T


Date First Available: April 28, 2024


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Jun 15

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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Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

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Top Amazon Reviews

    • Impressive Quality and Super Easy Assembly!
Size: Full Style Name: 9 inch Design: New Quick Assembly
I’m extremely happy with the ZINUS 9 Inch WonderBox™ Smart Box Spring! From the moment I opened the box, I was impressed by the thoughtful packaging and clear instructions. Assembly was quick and straightforward—I had it fully put together in under 30 minutes with no tools beyond what was provided. The build quality is excellent. It feels sturdy and supportive, with no creaking or shifting under the mattress. The 9-inch height is perfect—high enough to provide great clearance and support, but not so tall that it raises the bed too much. One of the standout features for me was how compactly it ships. It’s amazing how a full box spring fits into such a manageable box. This made moving it through doorways and tight hallways a breeze. Overall, ZINUS really delivered on both convenience and durability. If you’re looking for a reliable, easy-to-assemble box spring that doesn’t sacrifice quality, this one is a winner! ... show more
Reviewed in the United States on May 20, 2025 by K. Flickinger
    • Easy peasey
Size: Full Style Name: 9 inch Design: New Quick Assembly
I purchased this based on reviews. I recently got a memory foam mattress for my guest bedroom and I needed a foundation (box spring) for it. After doing some research this seemed like the best thing to purchase. When I got the box I was a little worried. It seemed like it had way too much tape on it. Was it a return? After opening the box it wasn't a return and everything was there. Maybe the extra tape was for the weight of the box. I looked at the pieces and pictures began to assemble. About 30 minutes later I had a box spring. The hardest part was putting in the screws for the center support. I didn't have my readers with me and seeing the holes was a small task. I put on the snug covering and put on the mattress. I think I'm going to give it a test tonight. If you're on the fence about this go ahead a get it. ... show more
Reviewed in the United States on May 14, 2025 by mylissa compton
    • Best Purchase Ever
Size: Queen Style Name: 5 inch Design: New Quick Assembly
I never write product reviews, but this was such an awesome purchase. This is the BEST box spring I have ever owned. If you’re on the fence about buying this product, or you’re trying to decide between options, here’s a number of reasons to go with this one. 1. Noise Level: NONE. Completely silent. This was my #1 reason for wanting a new box spring in the first place, and it does not disappoint. Our previous box spring (the traditional wood/spring kind) had become squeaky over the years, and kept waking up our 5 month old baby. This new box spring hasn’t made one tiny noise since day one - our baby has been sleeping through the night. Relief is an understatement. 2. Sturdiness: I have never felt so supported by my bed. It feels even better than when our previous box spring was brand new, so I know it’s not just because it’s new. I have chronic shoulder pain, and while a new box spring obviously isn’t a cure, I have been waking up significantly less sore for the first time in years. My husband doesn’t have the same pain issues, but he agrees that our bed feels much more sturdy and comfortable, because our bodies are better supported. 3. Assembly: So easy. I am not in my greatest shape (I did just have a baby), but I was able to put it together without my husband’s help. The box comes with some screws and an Alan key, and that’s honestly all that’s needed. The directions are pretty easy to follow. I will say that the “Up” stickers were placed on the parts in a way that was a little confusing at times, but if you pay close attention to the pictures in the instructions, you’ll be fine. It took me less than an hour. I cannot recommend this box spring enough. Do yourselves a favor and purchase this. You can thank me later. :) ... show more
Reviewed in the United States on February 11, 2025 by cnelson1102
    • Sturdy metal grid
Size: King Style Name: 5 inch Design: New Quick Assembly
Sturdy metal grid that’s easy to assemble, requires only four bolts included. The product is quite heavy and requires a team of two to carry it up the stairs. The cover is very thin, it can use better materials. I installed two 1/8” plywood seamed in center by masking tape under the cover to provide more rigidity to the whole platform. ... show more
Reviewed in the United States on May 4, 2025 by Pro buyer
    • Easy to assemble and sturdy
Size: Full Style Name: 9 inch Design: New Quick Assembly
Literally so easy to put together, unboxed and assembled in under 10 minutes. Sturdy. And so much less to store if ever didnt need or moved.
Reviewed in the United States on May 23, 2025 by 4theloveof
    • close to perfect
Size: Queen Style Name: 5 inch Design: New Quick Assembly
I spent a ridiculous amount of time comparing prices and features before ending up with this purchase and I am so glad I did! Everything is perfect, all the parts, the fit, the engineering, even the finished look. Easy to put together with snap lock connectors. I have a relatively thin mattress and still can't feel the crossbars through it. This is day one. All the negative comments about bed foundations from other sellers don't seem to apply here. As for durability, my expectations are high but we'll have to wait and see. ... show more
Reviewed in the United States on April 18, 2025 by Amazon Customer
    • Terrible construction and won’t stay put together.
Size: Queen Style Name: 5 inch Design: 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
    • Great Product
Size: Queen Style Name: 7 inch Design: New Quick Assembly
So much better than the wood ones. Don't have to worry about bed bugs with these and the can be taken apart to move my new favorite box spring. Easy to put together
Reviewed in the United States on May 7, 2025 by Jaylynn

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