Not very strong. Item is thin shiny plastic which makes it look cheap and the illustration misleading. Instructions are not clear and item comes with a basic diagram which has some numbered parts but no instructions as to where they should go. Knobs fall out when you brush against the planter and the whole thing collapses if you try and move it. I contacted Wayfair about the lack of instructions and they were very helpful and said the manufacturer would be informed of the problem and would get in touch within a week which sounded great but that was several weeks ago and I am still waiting to hear from the manufacturer.