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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 $ 27.79
    Original price $ 27.79 - Original price $ 27.79
    Original price $ 27.79
    Current price $ 22.19
    $ 22.19 - $ 22.19
    Current price $ 22.19

    Foster 3653GS, 1/4" Industrial Coupler x 5/16" Hose ID, 3 Series, Automatic Slim Profile, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3653GS is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

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    Original price $ 27.79
    Original price $ 27.79 - Original price $ 27.79
    Original price $ 27.79
    Current price $ 22.19
    $ 22.19 - $ 22.19
    Current price $ 22.19
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  • Original price $ 28.39
    Original price $ 28.39 - Original price $ 28.39
    Original price $ 28.39
    Current price $ 22.69
    $ 22.69 - $ 22.69
    Current price $ 22.69

    Foster 3653GB, 1/4" Industrial Coupler x 5/16" Hose ID, 3 Series, Automatic Slim Profile, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3653GB is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

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    Original price $ 28.39
    Original price $ 28.39 - Original price $ 28.39
    Original price $ 28.39
    Current price $ 22.69
    $ 22.69 - $ 22.69
    Current price $ 22.69
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  • Original price $ 22.59
    Original price $ 22.59 - Original price $ 22.59
    Original price $ 22.59
    Current price $ 18.09
    $ 18.09 - $ 18.09
    Current price $ 18.09

    Foster 3603GS, 1/4" Industrial Coupler x 1/4" Hose ID, 3 Series, Automatic Slim Profile, Steel

    In stock

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

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    Original price $ 22.59
    Original price $ 22.59 - Original price $ 22.59
    Original price $ 22.59
    Current price $ 18.09
    $ 18.09 - $ 18.09
    Current price $ 18.09
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  • Original price $ 28.79
    Original price $ 28.79 - Original price $ 28.79
    Original price $ 28.79
    Current price $ 23.09
    $ 23.09 - $ 23.09
    Current price $ 23.09

    Foster 3603GB, 1/4" Industrial Coupler x 1/4" Hose ID, 3 Series, Automatic Slim Profile, Brass

    In stock

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

    View full details
    Original price $ 28.79
    Original price $ 28.79 - Original price $ 28.79
    Original price $ 28.79
    Current price $ 23.09
    $ 23.09 - $ 23.09
    Current price $ 23.09
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  • Original price $ 22.29
    Original price $ 22.29 - Original price $ 22.29
    Original price $ 22.29
    Current price $ 17.79
    $ 17.79 - $ 17.79
    Current price $ 17.79

    Foster 3303GS, 1/4" Industrial Coupler x 3/8" Male NPT, 3 Series, Automatic Slim Profile, Steel

    In stock

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

    View full details
    Original price $ 22.29
    Original price $ 22.29 - Original price $ 22.29
    Original price $ 22.29
    Current price $ 17.79
    $ 17.79 - $ 17.79
    Current price $ 17.79
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  • Original price $ 28.19
    Original price $ 28.19 - Original price $ 28.19
    Original price $ 28.19
    Current price $ 22.49
    $ 22.49 - $ 22.49
    Current price $ 22.49

    Foster 3303GB, 1/4" Industrial Coupler x 3/8" Male NPT, 3 Series, Automatic Slim Profile, Brass

    In stock

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

    View full details
    Original price $ 28.19
    Original price $ 28.19 - Original price $ 28.19
    Original price $ 28.19
    Current price $ 22.49
    $ 22.49 - $ 22.49
    Current price $ 22.49
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  • Original price $ 21.59
    Original price $ 21.59 - Original price $ 21.59
    Original price $ 21.59
    Current price $ 17.29
    $ 17.29 - $ 17.29
    Current price $ 17.29

    Foster 3103GS, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Automatic Slim Profile, Steel

    In stock

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

    View full details
    Original price $ 21.59
    Original price $ 21.59 - Original price $ 21.59
    Original price $ 21.59
    Current price $ 17.29
    $ 17.29 - $ 17.29
    Current price $ 17.29
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  • Original price $ 26.69
    Original price $ 26.69 - Original price $ 26.69
    Original price $ 26.69
    Current price $ 21.39
    $ 21.39 - $ 21.39
    Current price $ 21.39

    Foster 3103GB, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Automatic Slim Profile, Brass

    In stock

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

    View full details
    Original price $ 26.69
    Original price $ 26.69 - Original price $ 26.69
    Original price $ 26.69
    Current price $ 21.39
    $ 21.39 - $ 21.39
    Current price $ 21.39
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  • Original price $ 26.29
    Original price $ 26.29 - Original price $ 26.29
    Original price $ 26.29
    Current price $ 21.09
    $ 21.09 - $ 21.09
    Current price $ 21.09

    Foster 2903GS, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Automatic Slim Profile, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903GS is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 26.29
    Original price $ 26.29 - Original price $ 26.29
    Original price $ 26.29
    Current price $ 21.09
    $ 21.09 - $ 21.09
    Current price $ 21.09
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  • Original price $ 36.89
    Original price $ 36.89 - Original price $ 36.89
    Original price $ 36.89
    Current price $ 29.49
    $ 29.49 - $ 29.49
    Current price $ 29.49

    Foster 2903GB, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Automatic Slim Profile, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903GB is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 36.89
    Original price $ 36.89 - Original price $ 36.89
    Original price $ 36.89
    Current price $ 29.49
    $ 29.49 - $ 29.49
    Current price $ 29.49
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  • Original price $ 22.59
    Original price $ 22.59 - Original price $ 22.59
    Original price $ 22.59
    Current price $ 18.09
    $ 18.09 - $ 18.09
    Current price $ 18.09

    Foster 3203GS, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Automatic Slim Profile, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203GS is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 22.59
    Original price $ 22.59 - Original price $ 22.59
    Original price $ 22.59
    Current price $ 18.09
    $ 18.09 - $ 18.09
    Current price $ 18.09
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  • Original price $ 29.19
    Original price $ 29.19 - Original price $ 29.19
    Original price $ 29.19
    Current price $ 23.39
    $ 23.39 - $ 23.39
    Current price $ 23.39

    Foster 3203GB, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Automatic Slim Profile, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203GB is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 29.19
    Original price $ 29.19 - Original price $ 29.19
    Original price $ 29.19
    Current price $ 23.39
    $ 23.39 - $ 23.39
    Current price $ 23.39
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  • 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, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Automatic Slim Profile, 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
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  • 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, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Automatic Slim Profile, 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
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  • Original price $ 29.69
    Original price $ 29.69 - Original price $ 29.69
    Original price $ 29.69
    Current price $ 23.79
    $ 23.79 - $ 23.79
    Current price $ 23.79

    Foster 2803GS, 1/4" Industrial Coupler x 1/8" Female NPT, 3 Series, Automatic Slim Profile, Steel

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2803GS is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 29.69
    Original price $ 29.69 - Original price $ 29.69
    Original price $ 29.69
    Current price $ 23.79
    $ 23.79 - $ 23.79
    Current price $ 23.79
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  • Original price $ 25.69
    Original price $ 25.69 - Original price $ 25.69
    Original price $ 25.69
    Current price $ 20.49
    $ 20.49 - $ 20.49
    Current price $ 20.49

    Foster 2803GB, 1/4" Industrial Coupler x 1/8" Female NPT, 3 Series, Automatic Slim Profile, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2803GB is a Brass 1/4" industrial coupler from the Foster 3 Series — the m...

    View full details
    Original price $ 25.69
    Original price $ 25.69 - Original price $ 25.69
    Original price $ 25.69
    Current price $ 20.49
    $ 20.49 - $ 20.49
    Current price $ 20.49
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  • Original price $ 34.49
    Original price $ 34.49 - Original price $ 34.49
    Original price $ 34.49
    Current price $ 27.59
    $ 27.59 - $ 27.59
    Current price $ 27.59

    Foster SLSD13-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 3/8" ID x 13/16" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSD13-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the...

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    Original price $ 34.49
    Original price $ 34.49 - Original price $ 34.49
    Original price $ 34.49
    Current price $ 27.59
    $ 27.59 - $ 27.59
    Current price $ 27.59
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  • Original price $ 32.79
    Original price $ 32.79 - Original price $ 32.79
    Original price $ 32.79
    Current price $ 26.19
    $ 26.19 - $ 26.19
    Current price $ 26.19

    Foster SLSD11-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 3/8" ID x 3/4" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSD11-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the...

    View full details
    Original price $ 32.79
    Original price $ 32.79 - Original price $ 32.79
    Original price $ 32.79
    Current price $ 26.19
    $ 26.19 - $ 26.19
    Current price $ 26.19
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  • Original price $ 32.19
    Original price $ 32.19 - Original price $ 32.19
    Original price $ 32.19
    Current price $ 25.79
    $ 25.79 - $ 25.79
    Current price $ 25.79

    Foster SLSD9-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 3/8" ID x 11/16" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSD9-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

    View full details
    Original price $ 32.19
    Original price $ 32.19 - Original price $ 32.19
    Original price $ 32.19
    Current price $ 25.79
    $ 25.79 - $ 25.79
    Current price $ 25.79
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  • Original price $ 31.79
    Original price $ 31.79 - Original price $ 31.79
    Original price $ 31.79
    Current price $ 25.39
    $ 25.39 - $ 25.39
    Current price $ 25.39

    Foster SLSD7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 3/8" ID x 5/8" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSD7-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

    View full details
    Original price $ 31.79
    Original price $ 31.79 - Original price $ 31.79
    Original price $ 31.79
    Current price $ 25.39
    $ 25.39 - $ 25.39
    Current price $ 25.39
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  • Original price $ 43.79
    Original price $ 43.79 - Original price $ 43.79
    Original price $ 43.79
    Current price $ 35.09
    $ 35.09 - $ 35.09
    Current price $ 35.09

    Foster SLSC7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 5/8" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSC7-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

    View full details
    Original price $ 43.79
    Original price $ 43.79 - Original price $ 43.79
    Original price $ 43.79
    Current price $ 35.09
    $ 35.09 - $ 35.09
    Current price $ 35.09
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  • Original price $ 43.79
    Original price $ 43.79 - Original price $ 43.79
    Original price $ 43.79
    Current price $ 35.09
    $ 35.09 - $ 35.09
    Current price $ 35.09

    Foster SLSC5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 9/16" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSC5-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

    View full details
    Original price $ 43.79
    Original price $ 43.79 - Original price $ 43.79
    Original price $ 43.79
    Current price $ 35.09
    $ 35.09 - $ 35.09
    Current price $ 35.09
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  • Original price $ 33.19
    Original price $ 33.19 - Original price $ 33.19
    Original price $ 33.19
    Current price $ 26.59
    $ 26.59 - $ 26.59
    Current price $ 26.59

    Foster SLSB7-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Automatic Sleeve Lock, Water, Brass/SS

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSB7-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — ...

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    Original price $ 33.19
    Original price $ 33.19 - Original price $ 33.19
    Original price $ 33.19
    Current price $ 26.59
    $ 26.59 - $ 26.59
    Current price $ 26.59
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  • Original price $ 29.89
    Original price $ 29.89 - Original price $ 29.89
    Original price $ 29.89
    Current price $ 23.99
    $ 23.99 - $ 23.99
    Current price $ 23.99

    Foster SLSB7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Automatic Sleeve Lock, Brass

    In stock

    Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSB7-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

    View full details
    Original price $ 29.89
    Original price $ 29.89 - Original price $ 29.89
    Original price $ 29.89
    Current price $ 23.99
    $ 23.99 - $ 23.99
    Current price $ 23.99
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