Hi there, what do you know about "charcoal barriers". I have just replaced my Toyota air filter with a knfilter.. and yes I do believe they are better.. in the fitting instructions mention is made of a "charcoal barrier" that is fitted to some cars re the emission. Now the old filter has attached to the usual paper element a blue/white gauze type material. My question is simply this ;- is this the "charcoal barrier" if so then appartently I must refit it.. Thanks for you (anticipated) help.

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