I bought an extra one to see if using two would double up the buzz noise protection. Unfortunatly I learned the hard way that it took a huge bite out of the sound quality. Don't ever use more than one. So I have an extra one.

I paid $15 for the Ground Loop Isolator, and $3 for the Connectors (two double ended female). You need the connectors in order to use it.

I am asking $13 for isolator and the connectors shipped.