TrueSeal is the Industry"s best seal technology! This superior seal keeps food fresher longer. The soft plastic seal"s parameter allows for easy use. Transparent window allows for easy viewing of contents. The tempered glass container is oven safe up to 425 degrees Fahrenheit. The glass is made in the USA by Anchor Glass and has 5-Year Warranty. The glass is dishwasher safe. The lid is not oven safe but can be washed on the top shelf of your dishwasher.