MCMCustom Audio 50-7725 L/R Audio Balun

Does this include a pair or do you need to purchase two?

Can we use through Ethernet bridge or Ethernet swicth (poweline)? to aviod long ethernet cables

Do I have to buy to of these in order to extend the audio signal over Ca6 Cable to 50ft? 1 for sending and 1 for receiving??

So I’m an idiot, on the other side of this is an Ethernet port right? I only see one pic and don’t know the lingo