Zinus 9 Inch WonderBox(TM) Smart Box Spring, Grey, King | Quick Assembly Mattress Foundation, Durable Metal Frame, Slip-On Cover

I’m honestly impressed with this foundation. I bought the king size and was expecting it to be heavy and complicated, but it was actually very easy to put together. The frame feels solid once it’s assembled, and it doesn’t wobble or shift when you get in and out of bed. What I like the most is that it makes absolutely no noise. No squeaks, no movement sounds at all. The support is firm in a good way, and the surface feels steady under the mattress. It also doesn’t weigh as much as I expected, so moving it around wasn’t a problem. Overall, it looks clean, feels durable, and holds the mattress perfectly without sliding. The height is perfect to match the regular bed headboard. (4 " works )Great buy.

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. :)

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.

After putting this boxspring together, I don't think I'll ever purchase a pre-assembled one ever again!Assembly was pretty easy, and the box has everything you need, including an allen wrench and a small ratchet. The instructions were specific about what order to do things in, but I just laid the parts out on my floor in their correct position, and snapped them together as I worked my way around. The powdercoating on the pieces feels high quality, and I did not notice a single sharp edge or corner. The pieces are all light but quite sturdy. I wanted a solid surface for a memory foam bed, and this seems to fit the bill.Something that worried me a little was whether the metal pieces would clank against each other when everything was assembled, but I think it'll be nice and quiet. The only place that metal could touch metal, there's a thin foam pad to prevent noise.At first I thought the cover was slightly undersized, but after getting all of the corners on, the material on the edges curves up over the top just a little on each side. It looks very nice once the mattress is in place.The ease of breaking this down to move it is a huge selling point. I don't plan on moving again in my life, but a large boxspring is a PAIN to move up and down stairs. This breaks down into a small enough package that you could easily move it up a spiral staircase.I would definitely recommend this to anyone who wants a sturdy base for their mattress, and especially to someone who has a tight pathway to their bedroom.

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. Local retailers were quoting me 2-3 hundred for a traditional box spring. Apparently they aren't commonly used anymore which is the reason stated for the high prices.-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.Update 3/4/26:Still holding up. Haven't had to tighten anything and it's still quiet. Keep in mind though that this is being used for a childs bed but Mom and Dad do spend a fair amount of time getting in and out of it.

I bought this box spring based off of the reviews I read on here because they looked great and a lot of them mentioned the easy assembly. I had just purchased one of their beds and love it so I figured this product would be great too but when I opened the box it looked like a return as all of the zip ties had been cut off the metal pieces. When I started assembling the product it went very smooth until I got to the middle piece that you have to screw together. I had to flip the parts upside down for one of the screws to go in. The other screw would not foil in at all. It seems like the part wasn’t made properly for it to screw in. What the reviews said was a 30 minute set up was a 2 hour set up for me trying to get the screw in and widen the hole. I’m not too concerned about it since one of the screws went in and the metal slats are in place but for the price you should be getting a new product that all the pieces fit smoothly so I’m slightly disappointed about that. Other than that the product looks great and it seems pretty sturdy. Next time I would definitely spend a little bit more money at American Furniture or somewhere to make sure this doesn’t happen again.

I love it! It didn't take me any time at all to assemble—it's super easy and practical.

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.

esta muy chica de ancho mi colchon es individual y esta mas grande que esto pero de ahi en fuera facil de armar y no es muy caro

Went together so easy. Strong and sturdy. I dont have mine on top of a metal bedframe, using this to get an open frame look to match the loft bed I have over queen bed.. But for people saying its weak or bending on frame, your metal bedframe must have a center bar to support the center of this just like any quality frame should have supporting a wooden box spring. I didnt use the cover so cant make opinion on that. The mattress i have on it is an older 12 inch high Zinus hybrid that is heavy as heck. No creaking, rattles, and stays put. The mattress does sink down a bit in between bars when laying on it as a bigger person, but since in spare room not to worried about it. It would be nice if had few more cross bars but not a dealbreaker. For everyday use Id put a board under the area where main body weight would be. If bed frame in my room broke (which is a Zinus folding smartbase) Id buy one like this.

Love this box spring. Easy to put together and seems sturdy 😀

Super easy to put together, thank you.

easy to assemble, great for the price