A foam pump is an assembly of several precision parts, typically made from plastic (like PP or PE), silicone, and sometimes stainless steel springs.
1. Dip Tube: A long tube that extends to the bottom of the bottle to draw the liquid product up into the pump mechanism.
2. Housing / Chamber Body: The main outer structure that contains the internal mechanisms and often acts as the mixing chamber.
3. Piston: The core moving part. When the actuator is pressed down, the piston moves within the chamber. It has inlet and outlet valves (often tiny holes or flaps) that control the flow of liquid and air.