This is a direct replacement for most Subaru PERRIN Performance intakes systems including the Big MAF intakes. It will also work on any intake system which accepts a 3.125" filter.
PERRIN Performance filters feature a unique two piece design allowing the user to remove the foam filter element for easy cleaning. Easily run the element under a faucet for cleaning and ring out by hand. Simply slip the foam sleeve back over the filter frame and your ready to go.
PERRIN foam filters are made of reticulated polyurethane foam which offers a minimal air restriction. The filter element is sprayed with a special oil that adheres to the foam making the poly matrix sticky to retain dirt. Foam filters do not block dirt, they grab it, suffering only minimal drops in air flow as they filter dirt, maintaining air flow levels when other filters would clog.