Tetra Replacement Foam For Flat Box Filter Review AuntWrecker April 17, 2018 August 4, 2018 No Comments on Tetra Replacement Foam For Flat Box Filter Review Flat Box Filter Rplcmnt Foam Course and fine pads to be used in filters found in fk5, fk6 and sf1. Weight: 0.23 LBS. Manufacturers #: 19015 Our Model Number #: 956593 UPC: 046798190158