Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky-Clicky.
Err. Sorry about that. But that is a pretty accurate description of what these do (and sound like). What we have here is a relay module. You give it a high digital signal, it triggers the relay. You have options of Normal-Open or Normal-Close wiring to make things easier. It also uses a standard 3-pin Signal/V+/GND interface, so plugging it into things like the Electronic Brick, Grove, or Phidgets system is a breeze.
Just don't do anything dangerous with it. Seriously.