KeepCup LongPlay adds a removable tritan booster to our glass cup to create a twin-walled vessel. The booster increases durability and protects touch. For hot drinks, LongPlay will improve heat retention and insulate your hand from heat, and for ice drinks, LongPlay will keep them cold longer and prevent condensation. – Replacement parts available.– Dishwasher safe on top shelf, for best results hand wash.– Do not heat over 100C / 212F degrees.