Thank you very much for looking. m(_ _)m This is a petri dish with a lid. It's made of thick, sturdy glass. I have four more, so please contact me if you need a lot. I received this as a gift, but I don't plan to use it, so I'm hoping someone else can make use of it... (*^^*) The diameter is about 10cm. I think it's in good condition, but it's a used item that has been in someone else's hands, so please understand this before purchasing.