The basic effect is that the liquid in the glass diminisehs from a full glass to a fraction of its original contents. But it's not limited to that. Use it as a milk glass: Pour the milk into a paper cone and the milk vanishes. Or use it as a production glass where the liquid vanishes and in its place are flowers or a silk.
The glass measures about 1 5/8" across the mouth and about 5" tall. Made of plastic.