This is a replacement filter for Mitsubishi's J-Fan simultaneous intake and exhaust ventilation fan. It is a set of 5 filters. I am selling these because I no longer need them due to moving. Recommended for those who haven't replaced their filters in a long time. Filters get dirtier than you think. Why not replace them now? The compatible models are listed on the package, so please check the photos. Model number: P-06JHF