About this item NOTE: Due to a fragile glass product, this item is NOT a dishwasher safe item, please use with care! IDEAL CAPACITY: 15-Ounce; perfect for serving tea, coffee, whiskey, juice and others. ELABORATE DESIGN: Durable double layer construction remains cool and prevents condensation. TOP QUALITY: made of lead-free borosilicate glass, it’s heat-resisting and brilliance. Absolutely no air bubble on the walls. (up to 520°F ) WARM REMINDED: There is a small hole in the bottom of the cup, which is the unique trace of the manual blowing process.Not a flaw. Additional Details ------------------------------ Product description: About this item NOTE: Due to a fragile glass product, this item is NOT a dishwasher safe item, please use with care! IDEAL CAPACITY: 15-Ounce; perfect for serving tea, coffee, whiskey, juice and others. ELABORATE DESIGN: Durable double layer construction remains cool and prevents condensation. TOP QUALITY: made of lead-free borosilicate glass, it’s heat-resisting and brilliance. Absolutely no air bubble on the walls. (up to 520°F ) WARM REMINDED: There is a small hole in the bottom of the cup, which is the unique trace of the manual blowing process.Not a flaw.