Each jar is made from high quality soda lime glass material with pristine clarity and consistent wall thickness ensuring no weak points. | Featuring a high-grade stainless-steel clip system, engineered to create the perfect tension providing an airtight and secure seal every time. | Glass is best for storing / preserving and transporting food and drink. It is made from natural ingredients so no harmful chemicals or toxins can leak into the food. | Glass is BPA free and does not absorb odours, flavours, or stains | Kilner continues to tackle plastic waste with our ethos of REUSE, REFILL, RECYCLE.