Pro Call Blocker Version 5.0 - Black Edition One touch of a button blocks up to 1,500 unwanted phone calls from telemarketers, scammers, etc. EASY SETUP IN SECONDS - Just plug it between your phone and your wall jack NO BATTERIES REQUIRED - Runs from the electricity in your phone line EEPROM technology saves blocked numbers even if device is disconnected NO MONTHLY FEE - simply uses data from your existing Caller ID Plan