For nozzles and pump heads, everyone should know that it is necessary to place a spring inside the product center. The external pump, that is, the spring in the center of the nozzle/pump head, is visible externally, generally placed above the pump core. The assembly is directly connected to the spray head/pump head cap. The advantage of the external pump is that it is not in direct contact with the liquid in the bottle, which is environmentally friendly and hygienic, and can prevent 100% of the rust of individual springs from affecting the quality of the product in the bottle. Of course, this problem is rare, because most of the springs are Is processed. In addition, the power of the external pump is larger than that of the internal pump, so the general pump head uses more external pumps, which is suitable for more viscous liquids such as emulsion stock solution.