... or plastic screw, 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%,55%,etc.Cover1, Flannelet cover2, Knitted cover3, Coral fleece cover4, ... detection test.The hot water bag is made of by Natural Rubber material, also can with kinds of cover, it is ...