These shelves are awesome! And at a really great deal! (Amazon's price is WAY lower than other places I found them). The quality is far higher than the price. I bought two and these units are super sturdy and strong, while still being space efficient and easy to knock down and put back up for moving.

As long as they are assembled correctly they won't be moving at all. I have mine inside on thick carpet, they are heavy enough that there is no wobbling. If you are using them on a hard slightly uneven surface (like a garage floor) you can steady them with those rubber furniture feet pads (or bits of cardboard as long as your floor won't be getting damp).

The metal pieces are high quality. Very strong and solid. They are heavy. The weight of the metal parts is how the unit is extremely stable yet still minimal. No wasted space. Perfect for maximizing living space. I have an art studio in a small bedroom. I put two of these units in my bedroom (the one I sleep in) for extra storage to keep my studio as spacious/un-cluttered as possible. It worked out perfectly! Wish I had thought of it sooner. Haha

The shelf surface pieces are particle board. Particle board is super sturdy and can last a very long time. I like to cover particle board in paper to protect it from any damage that can cause flaking. You don't need contact paper (unless you want to create a waterproof surface). I use brown builders paper (or brown packing paper. Any kind of Kraft paper will do) and slightly watered down white glue. I do this to all my "modular" particle board furniture and it really is worth the time and mild effort. You will never have to deal with those crumbling corners again.

Assembly is very easy and the instructions are great. Good diagrams. You will want to use a rubber mallet (or a hammer and pot holder is a good substitute) to securely tap the shelf supports into the slots. You will need a second person to assist with the second level. And a second person makes laying in the shelf surface pieces much easier too.

It was shipped in a box with very minimal padding at the ends. The cardboard was common lightweight cardboard and not even reinforced or doubled. As a result, the wood shelves were slightly chewed up (cosmetic mostly that would not be visible when assembled).

As soon as I opened the box, I knew I hated it. The legs were flimsy, very light weight, and could easily be twisted. Even with the nice heavy coat of finish on them, they measured a mere .057 inch thick. The wood shelves were common particle board that was smooth on both sides. I expected hardened or industrial particle board for something claiming to be heavy duty. They measured slightly less than 3/8 of an inch and flexed easily as well. For something claiming to hold 800 pounds per shelf, I think these were woefully inadequate. The brackets that made this into a single shelving unit as show in the picture, had to be ordered separately for some reason - why?

I have a real hard time believing that the shelf would hold as much weight as stated! I thought I was getting something far more substantial. The only way I could use this and feel any surety around it, was if I attached it to a wall and reinforced it. I shouldn't have to do that. For my needs, I need far better shelves. I'm guessing these thin particle boards would quickly deform under even modest weight. But I need a free standing and sturdy unit, so I am not going to waste my time even putting it together.

In my opinion these are absolutely not heavy duty, but light duty only.

I bought this rack to replace a plastic one that gave up the ghost after 20 years. The tack is intended to hold some fairly heavy and/or bulky items in my workshop.

While it is a reasonably good rack, I'll not buy another one.

PROS:

- All the parts were there
- Fit really well in my space
- Frame and cross members well finished
- Once assembled, it is sturdy enough

CONS:

- The shelves are thin particle board and will absorb anything that spills. They are also likely to degrade over time
- The level-to-level construction is poorly designed and is prone to slippage
- The aluminum rivets give you one chance to assemble the structure "tightly". Any rework required a light preening of the rivets.

It works, it holds my gear (so far) and I'll look elsewhere for the next one I need.

Very irritated at this shelf. It's terrible. I was thinking it would be sturdy and I could put some hand tools and power tools on it. But no way. The shelfs are to thin. They bend just only with my hand resting on them while I was putting it together! I didn't even finish putting it together because it was missing the couples to connect the 2 levels together! I thought about exchanging it but I realized while putting it together it is most definitely not sturdy or as strong as it makes it sound. It would be a decent shelf for light things.
Also the feet are terrible. Super thin and sharp with no flat feet. So there it most definitely digs into whatever surface you set it on. And the lips that hold the board are not very big so if enough weight is on the shelf it can actually bend and slip through the edges that hold it! Terrible. Do not buy.

This particular model comes WITHOUT the couplers needed to attach the short legs together to reach full height. There are couplers in different models (UR -185WGB, UR-245WGB etc.) I ASSUME they realized the design error, corrected it and are using AMAZON to selling off the flawed batch. Hopefully I will be able to purchase the couplers separately... but this is seriously inconvenient, holding up completing assembly and use of the shelves.
They MAY hold 4000 lbs in some very specific, limited distribution of weight (maybe with 3750lbs on the bottom shelf seated on the floor???) but I would not try it with anything I valued). I have real industrial shelves out side ( the kind they use in Home Depot stores. NOT what they sell, the ones they USE in the stores) they do not even claim to hold 4000 lbs so pretty sure this is a bogus claim.