Pentair S7M400 Filter Inner & Outer Cartridge Set | 170146The Pentair S7M400 Filter Inner & Outer Cartridge Set 170146 is a replacement filtration cartridge pack built for Pentair Sta Rite System 3 S7M400 modular media filters. This cartridge set is an original genuine Pentair replacement that includes both the inner and outer filter elements needed to maintain proper filtration performance. The combined filtration surface area totals approximately 400 square feet, with the inner cartridge providing around