Controlable flow filter?

[freshwatergal]

Anyone have any names on these or where I might be able to find one? thanks!

 

[patryuji]

I have noticed that the Tetratec Whisper filters (from the model 20 on up) seem to provide a "flow control". Additionally the model 30 and up have a "bio-foam" separate from the changeable filter/charcoal media.

On the box of the Penguin mini and 330 it claims to be able to control the flow.