Before I purchased these domes, I read all the reviews and was a little concerned. These were some complaints about how they were a bit flimsy and the vent covers weren't permanently attached, etc. However I really wanted a taller dome for my 5" deep plug trays so that I could grow hearty plants before transferring them into my gardens (and to protect them from my cat while indoors...). One of the complaints was that the plastic walls were too thin and that binder clips the purchaser used to secure the lids to the trays caused them to tear. Armed with this knowledge, I decided to make "seat belts" for my growing systems. They work fabulously! You can buy strap material and fastener clips from your local or big box hardware store. I have ten 50 plug tray & dome systems. The materials to make these "seat belts" cost $4.50 for each tray. Worth every penny and they look great. Also, I have no problem with the vent covers. On top of all that, my seeds are coming up more quickly than I expected so I'm a happy gardener!