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Foster 3 Series Couplers

The Foster 3 Series is the 1/4" body industrial interchange, the most popular air coupler size for shop and industrial systems. This collection includes 3 Series couplers and plugs in brass, steel, and stainless with NPT, hose barb, push-on, and reusable terminations, plus automatic, sleeve guard, ball check, and dust cap options. Filter by thread, material, and coupler or plug to match your line.

  • Original price $ 21.39
    Original price $ 21.39 - Original price $ 21.39
    Original price $ 21.39
    Current price $ 17.09
    $ 17.09 - $ 17.09
    Current price $ 17.09

    Foster FM3003, 3 Series, Industrial Coupler, Automatic, 1/4" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster FM3003 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

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    Original price $ 21.39
    Original price $ 21.39 - Original price $ 21.39
    Original price $ 21.39
    Current price $ 17.09
    $ 17.09 - $ 17.09
    Current price $ 17.09
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  • Original price $ 2.39
    Original price $ 2.39 - Original price $ 2.39
    Original price $ 2.39
    Current price $ 1.89
    $ 1.89 - $ 1.89
    Current price $ 1.89

    Foster 10-3, 3 Series, Industrial Plug, 1/4" Male NPT, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 10-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

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    Original price $ 2.39
    Original price $ 2.39 - Original price $ 2.39
    Original price $ 2.39
    Current price $ 1.89
    $ 1.89 - $ 1.89
    Current price $ 1.89
    Save 21% Save %
  • Original price $ 14.99
    Original price $ 14.99 - Original price $ 14.99
    Original price $ 14.99
    Current price $ 11.99
    $ 11.99 - $ 11.99
    Current price $ 11.99

    Foster 3003, 3 Series, Industrial Coupler, Manual, 1/4" Female NPT, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

    View full details
    Original price $ 14.99
    Original price $ 14.99 - Original price $ 14.99
    Original price $ 14.99
    Current price $ 11.99
    $ 11.99 - $ 11.99
    Current price $ 11.99
    Save 20% Save %
  • Original price $ 3.79
    Original price $ 3.79 - Original price $ 3.79
    Original price $ 3.79
    Current price $ 3.09
    $ 3.09 - $ 3.09
    Current price $ 3.09

    Foster 10-3B, 3 Series, Industrial Plug, 1/4" Male NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 10-3B is a Brass 1/4" industrial plug from the Foster 3 Series — the most ...

    View full details
    Original price $ 3.79
    Original price $ 3.79 - Original price $ 3.79
    Original price $ 3.79
    Current price $ 3.09
    $ 3.09 - $ 3.09
    Current price $ 3.09
    Save 18% Save %
  • Original price $ 13.59
    Original price $ 13.59 - Original price $ 13.59
    Original price $ 13.59
    Current price $ 10.89
    $ 10.89 - $ 10.89
    Current price $ 10.89

    Foster 3103, 3 Series, Industrial Coupler, Manual, 1/4" Male NPT, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3103 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

    View full details
    Original price $ 13.59
    Original price $ 13.59 - Original price $ 13.59
    Original price $ 13.59
    Current price $ 10.89
    $ 10.89 - $ 10.89
    Current price $ 10.89
    Save 20% Save %
  • Original price $ 2.69
    Original price $ 2.69 - Original price $ 2.69
    Original price $ 2.69
    Current price $ 2.19
    $ 2.19 - $ 2.19
    Current price $ 2.19

    Foster 11-3, 3 Series, Industrial Plug, 1/4" Female NPT, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 11-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

    View full details
    Original price $ 2.69
    Original price $ 2.69 - Original price $ 2.69
    Original price $ 2.69
    Current price $ 2.19
    $ 2.19 - $ 2.19
    Current price $ 2.19
    Save 19% Save %
  • Original price $ 2.89
    Original price $ 2.89 - Original price $ 2.89
    Original price $ 2.89
    Current price $ 2.29
    $ 2.29 - $ 2.29
    Current price $ 2.29

    Foster 12-3, 3 Series, Industrial Plug, 1/8" Male NPT, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 12-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

    View full details
    Original price $ 2.89
    Original price $ 2.89 - Original price $ 2.89
    Original price $ 2.89
    Current price $ 2.29
    $ 2.29 - $ 2.29
    Current price $ 2.29
    Save 21% Save %
  • Original price $ 3.39
    Original price $ 3.39 - Original price $ 3.39
    Original price $ 3.39
    Current price $ 2.69
    $ 2.69 - $ 2.69
    Current price $ 2.69

    Foster 16-3, 3 Series, Industrial Plug, 1/4" Hose Barb, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 16-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

    View full details
    Original price $ 3.39
    Original price $ 3.39 - Original price $ 3.39
    Original price $ 3.39
    Current price $ 2.69
    $ 2.69 - $ 2.69
    Current price $ 2.69
    Save 21% Save %
  • Original price $ 4.79
    Original price $ 4.79 - Original price $ 4.79
    Original price $ 4.79
    Current price $ 3.79
    $ 3.79 - $ 3.79
    Current price $ 3.79

    Foster 11-3B, 3 Series, Industrial Plug, 1/4" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 11-3B is a Brass 1/4" industrial plug from the Foster 3 Series — the most ...

    View full details
    Original price $ 4.79
    Original price $ 4.79 - Original price $ 4.79
    Original price $ 4.79
    Current price $ 3.79
    $ 3.79 - $ 3.79
    Current price $ 3.79
    Save 21% Save %
  • Original price $ 21.99
    Original price $ 21.99 - Original price $ 21.99
    Original price $ 21.99
    Current price $ 17.59
    $ 17.59 - $ 17.59
    Current price $ 17.59

    Foster FM3103, 3 Series, Industrial Coupler, Automatic, 1/4" Male NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster FM3103 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 21.99
    Original price $ 21.99 - Original price $ 21.99
    Original price $ 21.99
    Current price $ 17.59
    $ 17.59 - $ 17.59
    Current price $ 17.59
    Save 20% Save %
  • Original price $ 23.49
    Original price $ 23.49 - Original price $ 23.49
    Original price $ 23.49
    Current price $ 18.79
    $ 18.79 - $ 18.79
    Current price $ 18.79

    Foster 3003GB, 3 Series, Industrial Coupler, Automatic, 1/4" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003GB is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 23.49
    Original price $ 23.49 - Original price $ 23.49
    Original price $ 23.49
    Current price $ 18.79
    $ 18.79 - $ 18.79
    Current price $ 18.79
    Save 20% Save %
  • Original price $ 12.99
    Original price $ 12.99 - Original price $ 12.99
    Original price $ 12.99
    Current price $ 10.39
    $ 10.39 - $ 10.39
    Current price $ 10.39

    Foster SG3103, 3 Series, Industrial Coupler, Manual, Sleeve Guard, 1/4" Male NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SG3103 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 12.99
    Original price $ 12.99 - Original price $ 12.99
    Original price $ 12.99
    Current price $ 10.39
    $ 10.39 - $ 10.39
    Current price $ 10.39
    Save 20% Save %
  • Original price $ 5.59
    Original price $ 5.59 - Original price $ 5.59
    Original price $ 5.59
    Current price $ 4.49
    $ 4.49 - $ 4.49
    Current price $ 4.49

    Foster 13-3B, 3 Series, Industrial Plug, 1/8" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 13-3B is a Brass 1/4" industrial plug from the Foster 3 Series — the most ...

    View full details
    Original price $ 5.59
    Original price $ 5.59 - Original price $ 5.59
    Original price $ 5.59
    Current price $ 4.49
    $ 4.49 - $ 4.49
    Current price $ 4.49
    Save 20% Save %
  • Original price $ 7.29
    Original price $ 7.29 - Original price $ 7.29
    Original price $ 7.29
    Current price $ 5.89
    $ 5.89 - $ 5.89
    Current price $ 5.89

    Foster 17-3B, 3 Series, Industrial Plug, 3/8" Hose Barb, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 17-3B is a Brass 1/4" industrial plug from the Foster 3 Series — the most ...

    View full details
    Original price $ 7.29
    Original price $ 7.29 - Original price $ 7.29
    Original price $ 7.29
    Current price $ 5.89
    $ 5.89 - $ 5.89
    Current price $ 5.89
    Save 19% Save %
  • Original price $ 21.49
    Original price $ 21.49 - Original price $ 21.49
    Original price $ 21.49
    Current price $ 17.19
    $ 17.19 - $ 17.19
    Current price $ 17.19

    Foster 3003GS, 3 Series, Industrial Coupler, Automatic, 1/4" Female NPT, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003GS is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 21.49
    Original price $ 21.49 - Original price $ 21.49
    Original price $ 21.49
    Current price $ 17.19
    $ 17.19 - $ 17.19
    Current price $ 17.19
    Save 20% Save %
  • Original price $ 3.79
    Original price $ 3.79 - Original price $ 3.79
    Original price $ 3.79
    Current price $ 2.99
    $ 2.99 - $ 2.99
    Current price $ 2.99

    Foster 17-3, 3 Series, Industrial Plug, 3/8" Hose Barb, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 17-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

    View full details
    Original price $ 3.79
    Original price $ 3.79 - Original price $ 3.79
    Original price $ 3.79
    Current price $ 2.99
    $ 2.99 - $ 2.99
    Current price $ 2.99
    Save 21% Save %
  • Original price $ 14.39
    Original price $ 14.39 - Original price $ 14.39
    Original price $ 14.39
    Current price $ 11.49
    $ 11.49 - $ 11.49
    Current price $ 11.49

    Foster 3603, 3 Series, Industrial Coupler, Manual, 1/4" Hose Barb, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3603 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

    View full details
    Original price $ 14.39
    Original price $ 14.39 - Original price $ 14.39
    Original price $ 14.39
    Current price $ 11.49
    $ 11.49 - $ 11.49
    Current price $ 11.49
    Save 20% Save %
  • Original price $ 22.19
    Original price $ 22.19 - Original price $ 22.19
    Original price $ 22.19
    Current price $ 17.79
    $ 17.79 - $ 17.79
    Current price $ 17.79

    Foster FM3203, 3 Series, Industrial Coupler, Automatic, 3/8" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster FM3203 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 22.19
    Original price $ 22.19 - Original price $ 22.19
    Original price $ 22.19
    Current price $ 17.79
    $ 17.79 - $ 17.79
    Current price $ 17.79
    Save 20% Save %
  • Original price $ 12.89
    Original price $ 12.89 - Original price $ 12.89
    Original price $ 12.89
    Current price $ 10.29
    $ 10.29 - $ 10.29
    Current price $ 10.29

    Foster SG3003, 3 Series, Industrial Coupler, Manual, Sleeve Guard, 1/4" Female NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SG3003 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 12.89
    Original price $ 12.89 - Original price $ 12.89
    Original price $ 12.89
    Current price $ 10.29
    $ 10.29 - $ 10.29
    Current price $ 10.29
    Save 20% Save %
  • Original price $ 14.99
    Original price $ 14.99 - Original price $ 14.99
    Original price $ 14.99
    Current price $ 11.99
    $ 11.99 - $ 11.99
    Current price $ 11.99

    Foster 3303, 3 Series, Industrial Coupler, Manual, 3/8" Male NPT, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3303 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

    View full details
    Original price $ 14.99
    Original price $ 14.99 - Original price $ 14.99
    Original price $ 14.99
    Current price $ 11.99
    $ 11.99 - $ 11.99
    Current price $ 11.99
    Save 20% Save %
  • Original price $ 15.69
    Original price $ 15.69 - Original price $ 15.69
    Original price $ 15.69
    Current price $ 12.59
    $ 12.59 - $ 12.59
    Current price $ 12.59

    Foster 3703, 3 Series, Industrial Coupler, Manual, 3/8" Hose Barb, Brass, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3703 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

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    Original price $ 15.69
    Original price $ 15.69 - Original price $ 15.69
    Original price $ 15.69
    Current price $ 12.59
    $ 12.59 - $ 12.59
    Current price $ 12.59
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  • Original price $ 19.89
    Original price $ 19.89 - Original price $ 19.89
    Original price $ 19.89
    Current price $ 15.89
    $ 15.89 - $ 15.89
    Current price $ 15.89

    Foster 3003HW, 3 Series, Industrial Coupler, Manual, 1/4" Female NPT, Brass (HOT WATER)

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003HW is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — th...

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    Original price $ 19.89
    Original price $ 19.89 - Original price $ 19.89
    Original price $ 19.89
    Current price $ 15.89
    $ 15.89 - $ 15.89
    Current price $ 15.89
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  • Original price $ 22.39
    Original price $ 22.39 - Original price $ 22.39
    Original price $ 22.39
    Current price $ 17.89
    $ 17.89 - $ 17.89
    Current price $ 17.89

    Foster FM3303, 3 Series, Industrial Coupler, Automatic, 3/8" Male NPT, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster FM3303 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 22.39
    Original price $ 22.39 - Original price $ 22.39
    Original price $ 22.39
    Current price $ 17.89
    $ 17.89 - $ 17.89
    Current price $ 17.89
    Save 20% Save %
  • Original price $ 13.49
    Original price $ 13.49 - Original price $ 13.49
    Original price $ 13.49
    Current price $ 10.79
    $ 10.79 - $ 10.79
    Current price $ 10.79

    Foster SG3603, 3 Series, Industrial Coupler, Manual, Sleeve Guard, 1/4" Hose Barb, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SG3603 is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 13.49
    Original price $ 13.49 - Original price $ 13.49
    Original price $ 13.49
    Current price $ 10.79
    $ 10.79 - $ 10.79
    Current price $ 10.79
    Save 20% Save %