These are really nice jars that I can use for many things with all the different sizes that come with it. So far I've been using the big ones for pasta and rice. They are not completely airtight as the lids have a very small vent hole in the rubber seals so if you want them air tight you can just seal the holes. I used a flexible uv sealant to test it out and it seems to work pretty good. The jars are also very durable as I've already accidentally dropped one and it didnt even get a scratch. I'm very satisfied with these and would recommend