Pump for dispensing a product

A pump for use with a device for containing and dispensing a product, comprising:

• a body member;
• a vessel defining a variable-volume chamber, the vessel including a first wall and a second wall, the vessel being on the body member in a partially-deformed, first position;
• an inlet slit on the first wall, the inlet slit being configured to open one way in response to a decreased pressure in the chamber;
• an outlet slit on the second wall, the outlet slit being configured to open one way in response to an increased pressure in the chamber.

A device for containing and dispensing a product, comprising:

• a container configured to contain a product;
• a body member on the container;
• a vessel defining a variable-volume chamber, the vessel including a first wall and a second wall, the vessel being on the body member;
• an air passage on the body member, the air passage including a first end and a second end, the first end opening into the container, the second end being selectively opened and closed by the vessel;
• an inlet slit on the first wall, the inlet slit being configured to open one way in response to a decreased pressure in the chamber;
• and
• an outlet slit on the second wall, the outlet slit being configured to open one way in response to an increased pressure in the chamber.