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Extreme Vibration Desiccant Breathers

The Watchdog® R Series Breathers are designed for applications where gearboxes and reservoirs are subjected to continuous vibration, such as railroad maintenance equipment, off-road vehicles, mining equipment, and others. They ensure optimum protection of equipment by prohibiting the entry of moisture and particulate contamination. The Watchdog® R Series Breathers are easily attached to the equipment by rugged steel pipe threads.

When the silica gel cartridge turns from orange to dark green, simply install a new replacement cartridge to the reinforced metal base.

Typical applications include:

  • Cranes
  • Railroad Maintenance of Way Equipment
  • Farm Implements
  • Construction Equipment
  • Off-Road Heavy Equipment


  • Water Vapor Adsorbent - The silica used in the Watchdog® R Series Breathers adsorb up to 40% of its own weight.
  • Color Indicating - When maximum adsorption is reached, the silica gel turns from orange to dark green, indicating replacement is needed. The silica gel used is chemically inert, non-corrosive, and does not contain cobalt chloride, a heavy metal.
  • Durable Construction - Watchdog® R Breathers are manufactured from rugged ABS plastic, impact modified acrylic, and metal base.
  • Easy Connection - Models are available with 1″ and 2″ rugged steel male pipe threads.
  • Reusable Bottom Cap - Allows the economic replacement of the desiccant cartridge.


Model No. Description Adsorption Capacity Thread Connection Height Width Air Flow Case Quantity
39150 R Breather 4.91 fl oz 1" MNPT 5" 5.2" 25 CFM 2
39151 R Breather 8.6 fl oz 1" MNPT 6.5" 5.2" 25 CFM 2
39152 R Breather 16.56 fl oz 1" MNPT 9.5" 5.2" 25 CFM 2
39153 R Breather 8.6 fl oz 1.125" female thread 6" 5.2" 25 CFM 2
39154 R Breather 8.6 fl oz 2" MNPT 6.5" 5.2" 25 CFM 2
39155 R Breather 16.56 fl oz 2" MNPT 9.5" 5.2" 25 CFM 2
39156 R Breather 21.47 fl oz 2" MNPT 12" 5.2" 25 CFM 2

Replacement Cartridges

The Watchdog® R Replacement Cartridges are used with Watchdog® R Series Breathers. When the orange silica gel has turned dark green, remove the reusable top cap from the bottom desiccant cartridge, dispose of the spent dark green desiccant cartridge, then use the same top cap with a replacement cartridge.


Model No. Description Replacement For
39160 Replacement Cartridge 39150
39161 Replacement Cartridge 39151, 39153, and 39154
39162 Replacement Cartridge 39152 and 39155
39166 Replacement Cartridge 39156
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