Safe Materials ----- The cup body is made of glass. And silicone cover and ring made of durable and Food Grade Silicone, they are Free From BPA. Wide Range of Temperatures ----- Endures a wide range of temperatures from -50℃to 200℃.It can be used in microwave and fridge. (Note: If you want to use a microwave to heat the cup, please remove the silicone first, otherwise the high temperature will cause the silicone to deform). Durable ----- Are you still hesitating to use this 350ml/12oz Reusable Coffee Cup? Highest Quality Borosilicate Glass for extra durability. Feature elegant designs reusable coffee cup is suitable for all people Every-Day-Use. Heat-Proof ----- The silicone ring makes the mug much easier to hold, drink from and heat protection. Although when the hot liquid in the cup is above 80℃, the silicone ring will be hot, but Portable coffee cup is still suitable for home, library, office, gifts etc. (Boiling liquid drops to 80℃, will take a few minutes). Superb Gift