I have a relatively expensive Air-O-Swiss 7135 humidifier. The Air-O-Swiss cleaning brush actually wears down the surface of the Ultrasonic element till it barely works. Air-O-Swiss refused to sell a replacement part. After much searching I found these and gave it a try. Works beautifully resorting full vapor to the unit. It did require swapping the leads from the original disc and the new disc and soldering but it was quite simple if you know how to solder. It is great to keep this $180 working with this inexpensive part. It is a pretty poor service for Air-O-Swiss to refuse to offer parts such as these. Our landfills are full of discarded products for that reason. Thank you mist maker.