Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: Does this funnel work with the small .5mm bottles?
Document: While, this did say mini funnel, it was a lot smaller than expected and wasn't going to work for me. I returned it.
It's my fault for not reading the description carefully. I imagined this to be a bigger funnel but turns out to be a mini one. Quality is great but the size is just too small for practical use. Due to its size, my uses for this funnel will be limited to filling spice bottles and maybe my oil jar.
This is a small, stainless steel funnel, and it is well made. Dimensions are 2 inches across, 2 1/4 inches in height, and the spout is 3/8 inch in diameter. I know it is a quirk of mine, but I like to pour fine Scotch ( Macallans, Glenfiddich, etc, ), from a 750 ml bottle for my friends. The big bottles are too cumber son. Re-filling the 750 bottle from a 1.75 liter is a mess and a waste !
A great little funnel, perfect for pouring multiple substances into bottles with little openings, built very nice, not much else to say... a great purchase
It works well with small containers. It came as described, and it arrived quick. You can't use this funnel with medium and large-size containers.
I needed a small funnel for pouring home-made vanilla extract into 2 oz jars. This is the perfect size for that. Very pleased. The quality is also very good.
This funnel is smaller than I thought and I don't feel is worth the money paid for the item. It is not very wide so anything you pour in it you must do very slowly. Good for liquids but will be too small for dry contents.
This funnel appears to be exactly what I wanted. I haven't had a chance to use it yet, but don't expect any change in my opinion.The neck is short enough to pour into small spaces without needing to be concerned about spillage. The funnel was packaged in a plastic bag in a box with the other items purchased on this order.
This product is perfect for my pouring oils (olive oil into an oil dispenser that does not leak oil all over my counter top everytime I use it for example), liquid seasoning sauces and salad dressings into a bottle. Glad I got it. If you like to make your own seasoning sauces or salad dressings this is an excellent help as it fits in those smaller bottles that one would use for pouring. It is also great for transfering fresh ground salts and spices from a larger bulk container into salt shakers. I am so glad I got this little thing.
This little gem solves that.
Answer: The opening of the smallest part of the spout is 9 mm.