Best Seller | RITTAL 3321700 Replacement Filter Mat, 3-1/2"x3-1/2" Replacement Compact Axial Fan Filter Media, Radiator Connection 4 19/32 in, For Use With 3237 Series, 15 cfm Fan, Media Material Chopped Polyester, Fits Fan Shape Square, 3 1/2 in Height, 3 1/2 in Width, 3/8 in Depth, Package Quantity 5 ... more RITTAL 3321700 Replacement Filter Mat, 3-1/2"x3-1/2" Replacement Compact Axial Fan Filter Media, Radiator Connection 4 19/32 in, For Use With 3237 Series, 15 cfm Fan, Media Material Chopped Polyester, Fits Fan Shape Square, 3 1/2 in Height, 3 1/2 in Width, 3/8 in Depth, Package Quantity 5 | | $24.19 go to store |