This is a different version of the Hydrostatic Glass effect, working on a principle which has been used as a scientific stunt, but not in the guise of a magic effect.
Liquid is poured into a glass. The glass is inverted, with a postcard covering the mouth. The hand holding the postcard is removed, and the postcard and liquid stay suspended. Then the postcard is removed, and the liquid still remains suspended in the inverted glass, which is turned right way up, and the liquid poured out of the glass.
In this Version, the effect is performed with a crystal clear glass, and there is nothing to add or take away. The effect performs just as it reads.