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

Input:
Question: Is the see through part plastic or glass? Is there like a little bag you put in it?
Document: Super cute and sturdy. I didn't realize these were glass when I bought them. But we use them for cereal so the kids like that they can see what kind is in there.
These canisters are a brillant red for those who like this color. Glass with a surround and slim for those with limited counter space. The see through opening makes it easy to know what each contains. Great price and fast delivery.
These are very pretty canisters and they are red I really like them. They were just right for my kitchen and they even gave me a little more space on my countertop.
These are alright if you're not going to be using them a ton. Great decorative pieces, but the threads for the lids are rough and they have trouble being put on properly. They're cheap and feel like it.
I do like theses very much, when they were delivered the tallest canister had had a dent in the lid . Not the companies fault but instead of sending me another set they put $5.83 back in my account! This dissapointed me.
I was expecting the lids that just pulled off and pushed on but I was even happier that they twist on just like regular jar lids and this the three bigger ones are bigger than the three biggest ones of my other canister set and I love that I can see what I have and how much I have so I will know if I need more stuff.
expected them to be larger in circumference, height ok, tried washing them before using, but they got wet between the glass inside and the outside cylinder,  turned them upside down after inside dried for a few days to see if water will finally evaporate. hope it works.but the color is beautiful.
I really like these canisters. I still can't believe I bought this style, but they look very nice in our kitchen. The eye is drawn to them as soon as someone enters the kitchen from the back door.They are made of metal on the outside with a glass on the inside. The only thing I don't like about them is how water gets between the two layers (metal and glass) when washed. Even if they are not submersed in water, water gets in between.
It looks great on my counter and a blessing to be able to see when I need to restock. Love the color.
They keep everything fresh, easy to see, in addition to its attractive color and elegant style. A must have in all kitchens!
Answer: The entire inside is glass the outer material I think is tin it is very well made there is no bag  you just pour your flour or sugar right in the container. It is a nice set for the price.