The Replacement Aprilaire Expandable Media Filter 213 is compatible with Aprilaire 2200 (1213 Media Rail Kit upgrade is required), 2120 (1213 Media Rail Kit upgrade is required), Aprilaire 3210 or 4200 with air cleaner control, Aprilaire 1210, 2210 without air cleaner control. This Magnet Filter includes 4 wire braces and instructions for assembly. Note: This filter is not manufactured by Research Products Corporation. This is made with MERV 13 Media by Magnet by FiltersUSA (1 Pack)Magnet by FiltersUSA