This durable glass lid is made of heat-tempered glass for additional strength. It fits the Swiss Diamond 8" (20 cm) Fry Pan, Saucepan and Casserole (standard and induction models). It can also be used as a universal cover for any 20 cm cookware, including pots and pans. The handle features a rotating ring that opens and closes the adjustable steam vent - this allows the chef to control moisture in the pan without lifting the cover. The lid, like all Swiss Diamond cookware, is safe for oven use to 260 C (500 F). Do not expose to thermal shock - allow the lid to cool before placing it in water. Swiss Diamond heat-tempered glass lids feature adjustable steam vents which allow you to control moisture in the pan without even lifting the lid.