... , such as copperVol / size300ml – 2000mlFeature1, First grade natural rubber hot water bottle,2, Resistant to boiling water; 3, 100% leak proof4, Seamless moldedRubber content28%,30 ... after 100%pressure leak detection test.The hot water bag is made of by Natural Rubber material, also can with kinds of cover ... Inner, especially rigid and sharp things. BS1970:2006 Standard Natural Rubber Hot Water Bottle