Filter inside low flow modules 800518 & 800519 Back Catalog number: 201119 Manufacturer: SENSIDYNE Availability: In the manufacturer's stock Price on request - + Recommended 811-1708-01-R Gilibrator 3, Low Flow Dry Cell (Flow Range 5 - 45 Price on request 800485-171-2305 GilAir-3 R Pump, 5-Pack with Universal 5-Unit Char Price on request 811-9927-02 Cyclone, BGI4L O-Ring Kit & Gasket Kit Price on request