The C Band WR137 Passive Dehydrator is designed to be installed inline on C Band RF transmission systems and is designed to remove any moisture that is able to ingress into the waveguide. A C Band WR137 Passive Dehydrator is an cost-effective solution for drying small volume waveguide transmission systems. Typically a C Band WR137 Passive Dehydrator is fitted between an outdoor (hub or boom mounted) BUC/SSPA. The C Band WR137 Passive Dehydrator’s desiccant will last 12 to 18 months after which time a new descant cartridge can be fitted by simply unscrewing the cartridge and fitting a new. The desiccant is designed to change colour over time indicating when a new cartridge is required.