4PCS 6 * 6 * 8 micro switch touch switch button switch switch
Little clicky switches are standard input "buttons" on electronic projects. These work best in a PCB but can be used on a solderless breadboard as shown in this tutorial. The pins are normally open (disconnected) and when the button is pressed they are momentarily closed.
You can find an EAGLE cad package for these in switch-omron:B3F-10XX