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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.

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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 20% Save %
$ 28.79
$ 28.79 - $ 28.79
$ 28.79
$ 23.09
$ 23.09 - $ 23.09
$ 23.09

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

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...

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$ 28.79
$ 28.79 - $ 28.79
$ 28.79
$ 23.09
$ 23.09 - $ 23.09
$ 23.09
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 20% Save %
$ 22.29
$ 22.29 - $ 22.29
$ 22.29
$ 17.79
$ 17.79 - $ 17.79
$ 17.79

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

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...

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$ 22.29
$ 22.29 - $ 22.29
$ 22.29
$ 17.79
$ 17.79 - $ 17.79
$ 17.79
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 20% Save %
$ 28.19
$ 28.19 - $ 28.19
$ 28.19
$ 22.49
$ 22.49 - $ 22.49
$ 22.49

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

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...

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$ 28.19
$ 28.19 - $ 28.19
$ 28.19
$ 22.49
$ 22.49 - $ 22.49
$ 22.49
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 20% Save %
$ 21.59
$ 21.59 - $ 21.59
$ 21.59
$ 17.29
$ 17.29 - $ 17.29
$ 17.29

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

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...

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$ 21.59
$ 21.59 - $ 21.59
$ 21.59
$ 17.29
$ 17.29 - $ 17.29
$ 17.29
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 26.69
$ 26.69 - $ 26.69
$ 26.69
$ 21.39
$ 21.39 - $ 21.39
$ 21.39

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

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...

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$ 26.69
$ 26.69 - $ 26.69
$ 26.69
$ 21.39
$ 21.39 - $ 21.39
$ 21.39
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 26.29
$ 26.29 - $ 26.29
$ 26.29
$ 21.09
$ 21.09 - $ 21.09
$ 21.09

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

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...

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$ 26.29
$ 26.29 - $ 26.29
$ 26.29
$ 21.09
$ 21.09 - $ 21.09
$ 21.09
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 36.89
$ 36.89 - $ 36.89
$ 36.89
$ 29.49
$ 29.49 - $ 29.49
$ 29.49

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

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...

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$ 36.89
$ 36.89 - $ 36.89
$ 36.89
$ 29.49
$ 29.49 - $ 29.49
$ 29.49
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 22.59
$ 22.59 - $ 22.59
$ 22.59
$ 18.09
$ 18.09 - $ 18.09
$ 18.09

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

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...

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$ 22.59
$ 22.59 - $ 22.59
$ 22.59
$ 18.09
$ 18.09 - $ 18.09
$ 18.09
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 29.19
$ 29.19 - $ 29.19
$ 29.19
$ 23.39
$ 23.39 - $ 23.39
$ 23.39

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

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
$ 29.19
$ 29.19 - $ 29.19
$ 29.19
$ 23.39
$ 23.39 - $ 23.39
$ 23.39
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 21.49
$ 21.49 - $ 21.49
$ 21.49
$ 17.19
$ 17.19 - $ 17.19
$ 17.19

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

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
$ 21.49
$ 21.49 - $ 21.49
$ 21.49
$ 17.19
$ 17.19 - $ 17.19
$ 17.19
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 23.49
$ 23.49 - $ 23.49
$ 23.49
$ 18.79
$ 18.79 - $ 18.79
$ 18.79

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

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
$ 23.49
$ 23.49 - $ 23.49
$ 23.49
$ 18.79
$ 18.79 - $ 18.79
$ 18.79
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 29.69
$ 29.69 - $ 29.69
$ 29.69
$ 23.79
$ 23.79 - $ 23.79
$ 23.79

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

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
$ 29.69
$ 29.69 - $ 29.69
$ 29.69
$ 23.79
$ 23.79 - $ 23.79
$ 23.79
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 25.69
$ 25.69 - $ 25.69
$ 25.69
$ 20.49
$ 20.49 - $ 20.49
$ 20.49

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

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
$ 25.69
$ 25.69 - $ 25.69
$ 25.69
$ 20.49
$ 20.49 - $ 20.49
$ 20.49
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 34.49
$ 34.49 - $ 34.49
$ 34.49
$ 27.59
$ 27.59 - $ 27.59
$ 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

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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$ 34.49
$ 34.49 - $ 34.49
$ 34.49
$ 27.59
$ 27.59 - $ 27.59
$ 27.59
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 32.79
$ 32.79 - $ 32.79
$ 32.79
$ 26.19
$ 26.19 - $ 26.19
$ 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

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...

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$ 32.79
$ 32.79 - $ 32.79
$ 32.79
$ 26.19
$ 26.19 - $ 26.19
$ 26.19
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 32.19
$ 32.19 - $ 32.19
$ 32.19
$ 25.79
$ 25.79 - $ 25.79
$ 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

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 ...

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$ 32.19
$ 32.19 - $ 32.19
$ 32.19
$ 25.79
$ 25.79 - $ 25.79
$ 25.79
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 31.79
$ 31.79 - $ 31.79
$ 31.79
$ 25.39
$ 25.39 - $ 25.39
$ 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

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 ...

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$ 31.79
$ 31.79 - $ 31.79
$ 31.79
$ 25.39
$ 25.39 - $ 25.39
$ 25.39
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 43.79
$ 43.79 - $ 43.79
$ 43.79
$ 35.09
$ 35.09 - $ 35.09
$ 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

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
$ 43.79
$ 43.79 - $ 43.79
$ 43.79
$ 35.09
$ 35.09 - $ 35.09
$ 35.09
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 43.79
$ 43.79 - $ 43.79
$ 43.79
$ 35.09
$ 35.09 - $ 35.09
$ 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

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
$ 43.79
$ 43.79 - $ 43.79
$ 43.79
$ 35.09
$ 35.09 - $ 35.09
$ 35.09
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 33.19
$ 33.19 - $ 33.19
$ 33.19
$ 26.59
$ 26.59 - $ 26.59
$ 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

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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$ 33.19
$ 33.19 - $ 33.19
$ 33.19
$ 26.59
$ 26.59 - $ 26.59
$ 26.59
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 29.89
$ 29.89 - $ 29.89
$ 29.89
$ 23.99
$ 23.99 - $ 23.99
$ 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

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
$ 29.89
$ 29.89 - $ 29.89
$ 29.89
$ 23.99
$ 23.99 - $ 23.99
$ 23.99
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 30.89
$ 30.89 - $ 30.89
$ 30.89
$ 24.69
$ 24.69 - $ 24.69
$ 24.69

Foster SLSB5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 9/16" OD, 3 Series, Automatic Sleeve Lock, Brass

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSB5-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

View full details
$ 30.89
$ 30.89 - $ 30.89
$ 30.89
$ 24.69
$ 24.69 - $ 24.69
$ 24.69
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 30.29
$ 30.29 - $ 30.29
$ 30.29
$ 24.19
$ 24.19 - $ 24.19
$ 24.19

Foster SLSB3-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 1/2" OD, 3 Series, Automatic Sleeve Lock, Brass

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SLSB3-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the ...

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$ 30.29
$ 30.29 - $ 30.29
$ 30.29
$ 24.19
$ 24.19 - $ 24.19
$ 24.19
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 30.89
$ 30.89 - $ 30.89
$ 30.89
$ 24.69
$ 24.69 - $ 24.69
$ 24.69

Foster FMSD13-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 3/8" ID x 13/16" OD, 3 Series, Automatic, Brass

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster FMSD13-3 is a Brass 1/4" industrial coupler from the Foster 3 Series — the...

View full details
$ 30.89
$ 30.89 - $ 30.89
$ 30.89
$ 24.69
$ 24.69 - $ 24.69
$ 24.69
Save 20% Save %

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