Seem pretty flimsy. I don’t think they could hold up to the 600 pounds per shelf advertised. And they are smaller than made to seem in the image. Make sure you measure the space very precisely bc they are much smaller than made to seem in the image- I haven’t done exact measurements yet but they are not as tall as listed. 

They are kind of a pain to put together. The bars all just snap together with little posts that slide into an asymmetrical hole, but you really need a light weight rubber hammer to get the pieces fully in place bc they are a VERY tight fit.