For optimal insulation performance, preheat or cool the thermos with hot/cold water for 1-2 minutes, then pour in the drink. Make sure the silicone rings are properly fitted, the lid is tightly closed and the bottle is upright to prevent leaks. The special mouthpiece is designed to catch ice cubes and dispense the amount of liquid well from any drinking angle. The cup is also suitable for dairy products, fruit juices and sports drinks. Only be careful not to leave them in too long in order to avoid spoilage and rust. Do not fill carbonated drinks or dry ice into the bottle as it may expand and break.