On the older Calphalon (before the new Calphalon One - I haven't looked at it in person so I don't know about it) if the inside of the pan is the same matt gray on the instide as the outside - it's not non-stick. If it is non-stick, the surface will look a little slicker, be a little different color than the outside, and have a little silvery sheen to it. That's the way mine are.