why would i use the rca type output on my subwoofer

[robopup281]

I have a subwoofer that has 1 RCA input and 1 RCA output.
What is that output used for ?
In what situations might i need to use the output ?

 

[nitinvaid20]

To power another woofer or speaker

 

[SRIZ]

u can use RCA ports for connecting dvd,blurays players,xbox playstation,receiver, amplifier from ur sub woofer