airshield&trade contains a new twopart valve in the tube head which functions as a special protective shield it reliably protects the contents from oxygen.  the valve opens when the tube is squeezed and closes again when the pressure is released. so air cannot flow back into the sensitive contents. the products maintain their consistency and effectiveness, just as the pharmaceutical manufacturers intended them for their customers, even after the packaging has been opened and after daily use. neopac designed the airshield&trade tube and has applied for an international patent.  sourcehttpwww.neopac.com
