Its a 4 Way Dip switch which you can use either on a breadboard, or you can solder it to any proto board or PCB. The tiny and compact package will save you some space on the board and let you interfaces 4 on-off switches to your Circuit.
Looking to control lights and bulbs with microcontroller ? then, this digital AC switch boards is suitable for your application, this board is a great alternative for the solid state relay boards. This board comes pre-assembled with everything, all you need to do is to connect supply, load and digital interface pins