Crafted with high quality Borosilicate glass & Acacia wood lid with silicone insert. Borosilicate glass is a type of glass that contains boron trioxide which allows for a very low coefficient of thermal expansion. This means it will not crack under extreme temperature changes like regular glass. Its durability has made it the glass of choice for high-end restaurants, laboratories and wineries. The lid is made from Acacia wood, ethically sourced. These pantry jars provide a clean, safe and airtight protection for dried goods.