Filter Bags

I have been seeing these "filter bags" around some of these sites and I am haveing some problems with the roots getting in the pump so d these things really work? Sounds like the simplest greatest idea ever but I would like some feedback anyone have any pros/cons thanks

http://www.plantlightinghydroponics.com/water-pump-filter-bag-65in-x9in-p-2072.html

Nobody? I already bought a couple they seem logical and it says it is made of a fine mesh guess I'll see when they get here.

these need some modification but worth the couple of bucks.

I retract my earlier statements and would have to say this has done more harm than good. I have to rinse this fiter bag out daily and I am using B'cuzz NRG nutriants and others in the Atami lineup but still clogs the filter bag . I will stick to the homemade fish fiber filter I made and throw this piece of shit bag it the trash!