250ml Colored Mug made of High Borosilicate Glass Borosilicate glass is a special kind of glass which fuses two chemicals in high concentration: boron trioxide and silica. These safe and environmentally-friendly chemicals make borosilicate glass more heat resistant (can hold up to 150°C) than other forms of available glass. Borosilicate glass is safe to drink from, just like any other glasses. It helps you keep plastic waste out of landfill, which is good news for the environment. Food and drink from borosilicate containers often taste better in light of the fact that the material does not leach out, as it does in plastic jugs and other BPA-containing packaging. Perfect for enjoying hot and cold drinks for any season!