It works but has annoying problems
It works. Set up is remarkably easy. I set it to allow only certain numbers and it blocks all other numbers. BUT, when a blocked number calls, the phone rings once. It’s super annoying having it ring once 30 times a day, but it’s better than ringing several times or having to answer a scam call. Also, allowed numbers cannot be added manually. I tried. The instructions say to dial the number then press the “allow” button. That dials the number, and does not let you add the number to the allow list. To add a number to the allow list, that number has to call, then the number can be added from the call history list. It works, but every number you want to allow has to call first. With a few design improvements, this would be an excellent product. But as it is, it’s average. The call blocker is plugged into the main phone line.