Swiss Diamond uses tough， heat-tempered glass to ensure that our glass lids provide convenient durability. This 10.25" (26 cm) model was created for the Swiss Diamond Fry Pan and Saute Pan， but it could also be used as a universal lid to cover any 26 cm pot or pan. The adjustable knob can be rotated to open and close the integrated steam vent - this allows the chef to control moisture while cooking， without lifting the lid. It is safe for oven use， up to 260 C (500 F). Avoid exposing this or other glass articles to rapid heat changes such as exposing a hot lid to cold water.Make a perfect dinner every time with Swiss Diamond heat-tempered glass lids. Monitor your food while it cooks， and adjust the steam vent for advanced moisture control.