Twizz Mug doesn't have any top covers but has that secure the liquid in water-tight. The top parts is France Fashion style with unique designs for innovative opening and closing of the cup. The cup keeps the drink over 6 hours ice-cold or 2 hours hot. It is very convenient to use for outdoor sports, traveling, camping, hiking, driving, etc. and also you don't have to worry about your children spilling the beverage out of the cup. It is more outstanding than the common mug since it has a unique seal design for no leakage. The sealing ring connects the cup with silicon film closely, doesn't leak, good and convenient for outdoor activities, too. Also, the seal design gives you the ability to use it freely without the caution of spilling when you are driving. In addition, no cover but can seal drink become so interest.