Known as a Shower Bomb, these are formulated to work a little different than a bath bomb.
To use a Shower Scrubbie, hold it in your hand under running water.  Once wet, it will activate, creating a dense and creamy foam.  You scoop off the foam and rub it on your body! It leave behind smooth and moisturized skin.  
 
Each package contains 3 scrubbies, each is intended to be per shower.  
These are great for travel - no liquid!