At first the shelf is difficult to put together, but once you understand that the black things don’t actually snap tightly together, it’s a breeze. The actual shelving tightly slides over the plastic black things and this is what secures the shelves.

Haven't had a single complaint other than when I received it. One of the shelves was bent a couple degrees in shipping. It doesn't annoy me so I never sent it back. I don't think it was their fault either. Real sturdy, easy to move, and easy to keep put with the locks.

Very heavy duty shelving should last many years using to move plants in and out of greenhouse. Thinking about buying another one. That's how good it is.