Insulated thick gauge stainless steel outer body water bottle. Higher Durability. Leak proof. Food grade. Rust proof. Hygenic and 100% virgin material. Now keep things cool, healthy & fresh for 3 to 4 hours. Bottle Inner material is Plastic & outer is Steel. There is a small hole on the outer side of the bottle for saving inner material to be spoilt from hot water, leak proof. It is neatly covered so it doesn't effect the look of the bottle.