This is the best purchase I have made since I replaced my SUV with a Pickup!!! We received unwanted calls almost every day some starting at 6AM. Since use this cell phone jammer, my telephone rings only for the calls we want. The others have disappeared entirely. I finally have complete control of my telephone. Where has this been all my life? I spend my days training and riding horses. Prior to this purchase, when I return home in the evening, I would look at all the calls that would have disturbed me and erase them. I have call blocking in my home phone console, but even blocked calls ring once or twice. Now there is blissful silence! Not one unwanted call in two weeks.. Wonderful!!!