Thick glass but not too heavy
I have used both my bottles since purchasing and found that the Nozzles are sturdy and strong.  The bottles are nice and thick so they wont break easy and even though they are colored glass, I can still see how much fluid I have in them. I especially like that the odor of the contents does not leak out when sitting in the cabinet. A nice feature would have been to be able to spray upside down.  I can spray sideways but only until the tube doesn't sit in the liquid.  Overall, this is a great product.
Rating: 5 stars