I have to say that I was sceptical of the Stones after reading the info on there site. So I bought one to see what all of the hype was about. My amplifier transformer used to Hum, when I put the stone on top of the amp the hum went away. So I put several other objects on the amp, just to make sure that the weight of the stone wasn't the cure, nothing else worked. So, I'm a believer now and I just bought 4 more. Take it for what it's worth.