... copperVol / size300ml – 2000mlFeature1, First grade natural rubber hot water bottle,2, Resistant to boiling water; 3, 100% leak proof4, Seamless moldedRubber content28%, ... leak detection test.The hot water bag is made of by Natural Rubber material, also can with kinds of cover, it is very ... .7) Do not place anything on top of the bag Inner, especially rigid and sharp things. Durable Hot Water Bag