Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Tray very useful, but clamp unusable

I purchased this tray for headphone and other small item storage in my vocal isolation booth. I covered with carpet to reduce reflection, and mounted it on a pipe that runs vertically from the floor to the ceiling. The tray is very sturdy and a great size, but the clamp has proven unusable. I have not been able to tighten it or set it up in a way that does not make the tray droopy and unstable. I ended up rigging another clamp solution (with generous use of duct tape), so I am all set now. But only two stars because the tray did not work for me as delivered.