Due to the large volume of the bathtub, disassembly is not convenient, so the drainer can not be easily replaced after installation. Therefore, the quality and functionality of the bathtub drainer become particularly important. A good drainer must be able to quickly drain water, will not be oxidized corrosion, smooth surface will not harm the skin, good anti-spill function, prevent mosquito breeding, prevent sewer odor, not easy to plug.