Come on man, people are such retards...
They are BREATHER filters for the PCV system. They do not add any horsepower... How would they add Horsepower? Impossible

They are NOT to be used on the intake pipe... Some dude I know (complete idiot, one of those dudes who gets LED windshield squirters, lol) put one onn his intake pipe, cause he thought it was cool... His car actually lost power, because the intake was trying to suck air through the small BREATHER filter...
You could hear it, like a whisting/whining sound (and NO, it didn't sound cool, so don't do it)...

Save your money, please