The Sta-Rite S8M600 Modular Media Pool Filter uses a small and large filter cartridge. The Sta-Rite S8M600 filter holds one inner filter of 252 sq. And an outer cartridge of 348 sq. Available for individual sale or in a Replacement Kit, these cartridges are direct replacements and their durable design reduces maintenance for you. These Replacement Filter Cartridges capture fine debris, leaving you with clearer, cleaner pool water.