Sorry - I should have been more specific. It's this unit:
They used to sell them at Petco but I think that's no longer true (it's where I bought mine). It has a flow control lever on it, too. Overall I can't think of anything negative about this super little filter. Plenty of umph, flow control (I had it turned all the way down in the breeder box otherwise the cories were tossed all over the place). It really is a great little filter for $8!
I recommend it for that breeder box. It's almost as if they were designed for each other. The output on the filter fit perfectly snug, with no additional need for support.