These are really good shelves. I am 99% sure this is the OEM for the Amazon Basics shelves, because we own several of those and most of the parts are completely identical.At this size, they're a real challenge to assemble. You need a lot more space than the finished product takes up to put it together, and I strongly recommend having at least two people. Or three. Maybe four. Possibly five, but you're getting carried away at that point. Or the shelves are. Depends if you trust the other four people, I guess.The shelves are sturdy and swallowed all the weight we threw at them without burping. Which is good, because if you have burping shelves, get out of that haunted house ASAP!Because I am insane, I carried this piece by piece up two flights of stairs and a pulldown ladder into our attic and put it together there, where they freed up a ridiculous amount of space once I had finished. (If only they had freed up that space *before* I had finished, I'd have had enough room to assemble them properly, but although I've heard that time is a big ball of wibbly wobbly, timey wimey stuff, on this occasion it was behaving pretty linearly, so I had to make do.)The unit is very strong. An adult could probably walk on them, although they're not really designed for weight concentrated that much, so I'll leave that at "probably." Also, after the apocalypse, the unit will survive; the shelves will be able to be repurposed as fencing, doors, or window grates, and my inner child insists that the poles would be excellent martial arts weapons, though I did not test that either. That's my story and I'm sticking to it, and I have no idea how that gouge got in the attic ceiling drywall.I gave it four stars instead of five because at this weight and size, lowering the shelves onto the plastic retainers without knocking the retainers loose was maddeningly difficult. Somebody's going to figure out a small tweak that makes the next generation of these perfect.There were some shipping problems (the larger shelves ship as LTL freight, and LTL carriers just *love* residential deliveries) but the seller was very responsive and helpful in getting those worked out.