Insulates hot beverages up to 6 hours and cold beverages up to 24 hours * Durable, double-walled construction with vacuum insulation, not retain or impart flavors * Made of 18/8, food-grade stainless steel, no liner needed, 100% stainless interior * Extra-wide mouth ,no BPA, phthalates, lead, or other harmful substances * Rounded corners are easy to clean, external, stainless steel threads, easy to hand wash