I bought this product to try because I get 2-8 (!!!) per day. Morning to night I get robo-calls, "unavailable" number, silence, I even get calls showing my own number. This was becoming intolerable so when I first saw the cell phone jammer online I decided to try it. Simple is the only way to describe it. Take the unit and plug the short (8 inches or so) phone cable (included) from the CPR to your portable home phone base, base to line (as normal...) and robo-calls go away! Annoying robo-calls have dropped dramatically to sometimes one or NONE a day. I LOVE IT!!! BUY ONE OF THESE CALL BLOCKERS - KEEP YOUR SANITY! Recommended highly.