High-Grade Glass for Hot & Cold Resistance, 34 oz. High-Grade Borosilicate Glasses & Food-Grade Stainless Steel. It can withstand temperatures from -40°F to 300°F, it's HOT & COLD RESISTANT, and refrigerator safe. You can enjoy cups of hot coffee during the winter to warm up, and iced coffee in the summer to feel more energized without worrying about cracking. The Food-Grade Stainless Steel is resistant to heat, wear, and tear, preventing from bacteria growth while being easy to clean and sanitize. Like new, hardly used.