Im not sure what material it is but the pans are pretty heavy and feels like cast iron pans, but its not as heavy as cast iron. This makes the pans really sturdy and it feels pretty nice. Pans were non stick and very easy to use, in terms of size, I would say its good for 3-4 people worth of food. I really like the pans but something to be aware is the lid is pretty big in order to fit multiple size pans. So if you have a small hob and you tend to fill the hob with pans then the lid takes up a bit of space.

Only other thing to be aware is the weight. The weight makes it really sturdy (not flimsy at all) but at the same time, it can be a bit heavy if you want a pan that can be lifted all the time.