I am currently on my second set, which I bought 6 years ago. These things are awesome Not sure what the plastic is but nothing sticks to it, quick rinse with hot water usually cleans them up They are durable, obviously, as I have had this set 6 years and still use them every day. The only reason I am looking to buy a third set is because they aren't dog proof, left 9 of the small and medium on the counter with rice to cool slightly before refrigerating.Microwave safe, dishwasher safe, I have had no problems with boiling them or freezing them.They aren't cutesy looking or color coordinated. BUT, the whole set stores in my cabinet in the same space as a dinner plate, they all use the same lid which is very convenient, and they stack and fit in my fridge and freeze nicely. And they seal well. Love them