What materials are the always fresh containers?

No they don't! Always Fresh Containers are flimsy and cheaply made. They lack durability and you can't see what's inside very well because of the solid cover and dark green sides. The biggest knock is that they rotted the broccoli, celery and cauliflower I stored in them in record time. I had much better performance out of a zip lock bag! I followed the instructions that require the stored items to be 'moisture free', but this was a major hassle as anything sealed up and put in a fridge will suffer from condensation. This is the worst product we've purchased in years. Don't be fooled by the infomercial! Don't waste your money!

However....

I was skeptical but I thought I would try them at a set was on sale for $7 but it really does work! I buy a lot of fruits and veggies and it always goes bad before the end of the week before I can eat them but not this time...it did keep them fresh long enough for them to be consumed...I did notice some condenstation but it was easy to wipe up...fruits and veggies still nice and firm and tasty...strawberrys, grapes, peppers. I am not sure how long things are supposed to keep but a week is enough for me! I was so impressed I bought another set and have put a set aside for an xmass present. Really...