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

Input:
Question: Could you give me the inside measurement of the opening for filling?
Document: I've read other reviewers and I just have to say, &#34;What are you doing?&#34; We haven't had any leakage with our pen. My kids use it and haven't squeezed it so hard the top pops off. Maybe those reviewers had a defective cap? I'm sure, as some reveiwers have suggested you could do the same with a ketchup bottle, but the removable bottom makes for easier cleaning. I did not try and mix batter inside the bottle.
As a pancake pin it works well. I wish the pin opening was slightly smaller in diameter but I sure I will improve with practice. Very easy to clean.
I love this. Easy to fill. Easy to clean. The concept is great. I even give them as gifts and people love it.
Give it a try.I wrote out words and they turn out amazing. I'm not an artist at all, so my designs are horrible. I won't knock the pen for that.
Good idea, bad execution. The seals are terrible and leak water, the pancake mix must be put into the container using a funnel or similar method as the opening is smaller than the diameter of my measuring cups.
I bought one for myself, and one for a co-worker who saw it when it was delivered. Ordered a 2nd one before trying it out. Makes a complete mess. If you try to mix pancake batter, too much air in the bottle. It's like shaking a can of soda and opening it up.
I actually bought this to be a honey dispenser, and it is excellent! The opening is big enough that the honey flows easily, and when I stop pressing on the bottle, they honey gets sucked back in. No dripping mess! The lids just snaps on and off, and since the bottle can be screwed off from the top or bottom, it is really easy to clean. I just love it!
My cake pops maker bottle cracked after 3 uses & it's so much easier to make cake pops w/a bottle that I needed a replacement. This comes apart completely for cleaning (didn't discover that the bottom unscrewed til after I'd spooned it all into the smaller top opening), pours evenly, & feels like sturdier plastic than what I had before.
I thought this would be an easier way to dispense batter into my waffle iron. Not so much. Only about a third will come out easily. the rest just clings inside. Clean up is more difficult then simply using a batter bowl. Cant say it would be any better on pancake batter.
Never mind the pancakes. I use this for my bulk purchase oyster sauce. Its convenient to have a container large enough to fit half the can of sauce so I don't have to take up too much freezer space. This did the trick. I'm giving it an A+ for the size and the really large opening that doesn't dribble sauce all over the opening. Oyster sauce is a rather thick molasses like sauce, for those of you that aren't familiar with it, so a large opening is very necessary.
Answer: The following are ID measurements: bottom opening 2 3/8", top opening 2" and silicone tip 5/16".