So I got a few of these and stacked them up until I couldnt go any higher and let me tell you, its made a major difference. It beeps a couple of times when activated then stops -this gets you in the right location and you can press again to fine tune the location. Though it appeared halfway decent from 5 or more feet away, the closer people got to it, the more it was obvious how badly damaged the product was. It was truly all I ever wanted until I opened the package. However the sound does h. I mean they are thumping in my ears. Geht ja nicht nur um die Breite, sondern auch um die Länge. using one piece each time, both of them definitely would supply my 8 hour work shift worth of music and podcast! Sent back waiting on the next size up I was looking for great sandals to use on my vacation trip to Europe.