Double wall cup - ideal for tea and coffee (250 ml). Insulated double walled glass, heat resistant for any drinking.Thermo Mug for hot and cold drinks, as the double-walled glass is mouth blown. The double wall insulated glass design creates a thermal effect, keeping your drink hot or cold for a long period while the outer glass remains safe to touch. Never Burn Your Fingers! Remark: there will be a small, circular mark on the inside rim of the base of the glass where the blowpipe was removed during production. This mark is normal for all mouth blown glass.