The spine is actually hollow, not solid, causing it to be unstable

The spine is quite heavy duty metal, so its not easy to spread or force open to get the shelf inserted.

The new spine worked perfectly, and I get compliments on it all the time

But,the shelves are unnoticeable when stacked with books and I could not find a less expensive spine so far

Spine was bent/dented

Putting the shelf together went rapidly at the start, but when I got to the point of inserting the middle shelf into the spine I noticed the spine was pinched, and the shelf wouldn't go in.

I deducted one star because the spine is too easy to bend, surprising given its weight.

I was worried about the items on the top shelves if the spine was even a little unstable, but both the base and the spine are quite heavy and sturdy.

One of them arrived with a warped spine that wouldn't take one of the most important

The spine wobbles a bit when full with books - something to be aware of if you have small children