This is, without a doubt one of the finest pieces of utility apparatus ever created. The apparatus supplied consists of what appears to be an ordinary transparent clear plastic glass. Basically, the effect is that the liquid in the glass visibly diminishes from a glass full, to a fraction of the original contents. You can use this as a milk glass--you apparently pour a glass full of liquid into a paper cone, from where it vanishes. Or hold the glass out at arms length, and place a straw in your mouth. Now, as you suck through the straw, at the other end--the liquid visibly diminishes, even though it is three feet away. Or you can have an assistant hold the glass at one end of the stage, while you suck through the straw at the other end--and the liquid visibly diminishes. Or have a puppet or Vent doll "drink" the liquid! Our instructions give you many ideas for its use. The glass we supply "opens" for easy cleaning, and is an excellent utility or comedy prop at a very affordable price.