Check the listing for details. Federal Signal 300CK Connector Kit SelecTone. Condition: New – Open box. Listed at 48.00 USD. Cleaning out my office and business storage. New, never been used Federal Signal 300CK cards. I marked this in Item Specifics to be "New - Opened Box" because I have had these on the shelf in my office for a while, but they are new and unopened. SelecTone Connector Kit, 10 Vrms - Interfaces SelecTone speaker/amplifiers with an existing paging system. Works in 25 or 70 Vrms systems. Creates a balanced line SelecTone System For Use With: Speaker/Amplifier, 300MB, 300MC, 300VSC-1, 300SCW-1 and 300SSC Model SelecTone Command Unit