Filter inside low flow modules 800518 & 800519 Back Catalog number: 201119 Manufacturer: SENSIDYNE Availability: In the manufacturer's stock Price on request - + Recommended 910-0910-NO-R GilAir-Plus Data Logging Single Starter Kit, Bluet Price on request 811-9919-EU GilAir-3/5 BDX-2-Euro Five Unit Charger, Universal Price on request 783-0015-01 Lithium Ion Replacement Battery Pack for Nephelome Price on request