Unfortunately, I could not find a "free" frequency, even if I tried to use what it's written in the manual. I had interference in every lounge I played. And plus, the button on the receiver could have a sign, to see the level properly. I made it myself with some white paint. More than that, I don't like the fact that the battery level appears so late after you turn on the receiver. More than often I was in a hurry to see the level and it was so embarrassing to wait until it was there. The light that shows that the battery is almost depleted is not very clear either. I had a better one, but it's not compatible with this sender.