Hi there!
How would compare a mattbreaker (I've never heard of it!) to the Furminator? Indy still has massive undercoat and is shedding lots!
It cuts the undercoat out-completely strips it, if you're not careful!
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=843
I use the one called (lol) matbreaker! It has sharp blades and will completely remove and undercoat. The furminator doesn't have a sharp blade, but I've never used one either!
I know with the matbreaker, I used it to remove undercoat while showing (to even up the topline, and remove the undercoat when there was too much), and it would very easily remove everything but the topcoat.
It also removes the shedded hair. It works even better when it's paired with the Chris Christenson ( http://www.chrissystems.com/brushes.htm ) pin brush. The wooden one, with 1" pins. Because the matbreaker cuts out the undercoat, the brush (with the really long pins) can get to the skin (and through all of the hair-wonderful in shedding season!) even easier.

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