Buyers beware! A couple years ago I bought some air powered filters, and a whisper air pump, model 100, to power them all.
After a while the air pump kept putting out less and less so I eventually gave up and went to individual smaller pumps.
I have in the mail as we speak a new sponge filter for my 55g. I dug out the forgotten whisper blue dome, and decided to see if it was worth fixing. Removal of the cover was shocking. With the potential for it to literally be shocking. The wire was pinched almost all the way through, with the insulation sliced away in several spots on the 2" of wire between the housing and what I will call the motor.
The wire was cut on the neutral side, and the hot side was pinched, but the insulation not cut. If it had, it could have very, VERY easily started a fire. Or shocked me when I picked it up to move it. I, for one, dont believe in isolated incidents regarding quality control.
A second note, both diaphragms were ruptured. It was only in service for a few months.
The moral of the story... If you own a whisper blue dome, throw it away and replace it or at the very least remove the cover and inspect it!