Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Are containers of this brand air tight and leak proof?
Document: I had read many reviews in advance, and TrueSeal had the best rating of all glass containers tested. Well, I now wonder how bad the others were!I filled the glass container a bit more than half-way with water, dried the lip and put the lids on as tight as possible. I then sloshed it around and it was ok, but as soon as I turned it upside down it started to slowly leak out of the sides.
I have bought these storage dishes in varied sizes in the past few years. I like that the dishes are glass, no plastic food contamination with these. I think the lids are silicone. The lids fit well and yes the rectangle ones may leak if you put liquid in them and swing them around to try to lmake them leak. The 90 degree of the glass corners can't be made exactly like the lids so some tiny leaking can happen. This never happens with the round ones.
I've been searching high and low for glassware that can go from fridge to oven that also has a "sealing" lid. I didn't need it to be air/watertight. I mean, if it did, great, but since I wouldn't be packing these for lunch or juggling them in the street, just a cover to keep the lasagna smells out of the fridge would be nice. These looked great but as usual, the lid was far from perfect. I tried the "push down to burp" trick.
The glass bottoms I put in the dishwasher, but I do the  tops by hand. I will greatly reccomend these storage containers to any efficient housekeeper or cook.
Been switching to glass containers for health reasons and although heavier-these are the best.Anchor Hocking makes great products.I love the lids.
The quality of the glass and lid is excellent. Lid has a thick rubber edge that makes a secure easy seal. Love these and plan to use them to replace my flimsy plastic storage containers.
Love these practical and colorful containers. They are great for transporting meals to events. Makes clean-up easy when leftovers can just be covered and stored. I like the decreased use of plastic wraps and disposables.
These containers are really very good for storing food. The best thing about it is you can cook and also serve at the same time.I needed an itemsuch as these containers to make cooking easier for me and I must say,they work wonderful. Thank you for making such a good product.
I think these storage containers are amazing! I wish people would stop giving low star ratings for shipping errors and misunderstandings. This product is very well made and has a great variety of sizes. I highly recommend these products.
The lids on these absolutely do not seal. Its almost like they weren't even made for the containers! To even get them to stay on, you have to push them down like a diaphram, which then leaves gaps along the sides. Horrible product. Stay away. I'll see if I can upload a picture here to illustrate.
Answer: I don't actually know for sure,but I do believe they are air tight and leakproof because the seal is very tightaround the dish. Just make sure when you wash the seal,to let it air dry completely,or stretch the seal outward towards you to wipe clean&dry.; I had an experience where I didn't  wipe dry the seal and had to throw it out becauseit turned black. But I do think they are good and air tight and leak proof.  Good luck,and I hope this has helped you.