Product review (5 stars): Good for whole house humidifier
I have a whole house humidifier attached to my gas furnace in the basement and it would make an obnoxious hammer sound whenever the solenoid closed to shut off the water going over the humidifier pad.  This completely got rid of the noise.  I will try to upload a picture so you can see the installation.

The only complaint I have is the seller should have taken one out of the package and posted a few pictures of it.  It would have given better confidence that I was ordering the right thing.