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111 North 14th St • PO Box 218 • Coshocton, OH 43812

Filler Breather – Threaded Style

These filler breathers have a threaded fitting, making them easy to install as filler ports for hydraulic reservoirs. Filler breathers have a unique design which provide air flow while keeping out contaminants and particles. Essential in heavy industrial environments.


  • Breathers provide clean air flow into reservoirs where there is an exchange of air during changes in tank fluid levels
  • Available with grip cap as a standard product
  • Easy to install


  • Steel cap with multiple cap finishes
  • Compatible with petroleum based fluids
  • OBT-P style (pressurized)
    • Air intake valve opens at 0.435 PSI/3 KPԚ
    • Relief valve setting at 5 psi/.34 Bar
  • OBT style (non-pressurized)
    • Air flow to 30 CFM/850 LPM
    • Operating temperature up to 212° F


  • Zinc, chrome and black e-coat (zinc cap standard)
  • 3 micron (non-pressurized), 10- and 40-micron filters available – 10 micron standard
  • Contact factory for dipstick labeling options

Cap FinishCode
Black E-CoatB
Chrome PlatedC
Zinc PlatedZ
3 Micron - OBT only3
10 Micron10
40 Micron40
Fitting Type SizeCode
BSPP3/4 BlackB-3/4 BL
NPT3/4 BlackN-3/4 BL
SAE1-1/16 BlackS-12 BL
Available OptionsCode
All dimensions are in inches and for reference only.

How to Order: OBT-P (pressurized) series - Chrome Cap, 1/2" NPT with 40-micron filter = OBT-P-C-40-N-1/2

StyleCap FinishFilterFitting TypeOption

How to Order: OBT (non-pressurized) series – Chrome Cap, 1/2" NPT with 40-micron filter non-pressurized = OBT-C-40-N-1/2

StyleCap FinishFilterFitting TypeOption

OBT-P Pressurized Cap

OBT Non-Pressurized Cap