The premium series "Boroseal" is suitable for freezing down to -20 °C and is dishwasher and oven safe up to 400 °C. The base is made of high-quality borosilicate glass. The containers are 100% airtight and watertight, completely odorless, and flavor-resistant. The special closures are easy to open and close, even with one hand. They have an almost unlimited lifespan.