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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 %
$ 403.00
$ 403.00 - $ 403.00
$ 403.00
$ 323.00
$ 323.00 - $ 323.00
$ 323.00

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

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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$ 403.00
$ 403.00 - $ 403.00
$ 403.00
$ 323.00
$ 323.00 - $ 323.00
$ 323.00
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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 %
$ 513.00
$ 513.00 - $ 513.00
$ 513.00
$ 412.00
$ 412.00 - $ 412.00
$ 412.00

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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$ 513.00
$ 513.00 - $ 513.00
$ 513.00
$ 412.00
$ 412.00 - $ 412.00
$ 412.00
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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 %
$ 398.00
$ 398.00 - $ 398.00
$ 398.00
$ 317.00
$ 317.00 - $ 317.00
$ 317.00

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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$ 398.00
$ 398.00 - $ 398.00
$ 398.00
$ 317.00
$ 317.00 - $ 317.00
$ 317.00
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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 %
$ 503.00
$ 503.00 - $ 503.00
$ 503.00
$ 401.00
$ 401.00 - $ 401.00
$ 401.00

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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$ 503.00
$ 503.00 - $ 503.00
$ 503.00
$ 401.00
$ 401.00 - $ 401.00
$ 401.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 385.00
$ 385.00 - $ 385.00
$ 385.00
$ 308.00
$ 308.00 - $ 308.00
$ 308.00

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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$ 385.00
$ 385.00 - $ 385.00
$ 385.00
$ 308.00
$ 308.00 - $ 308.00
$ 308.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 476.00
$ 476.00 - $ 476.00
$ 476.00
$ 381.00
$ 381.00 - $ 381.00
$ 381.00

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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$ 476.00
$ 476.00 - $ 476.00
$ 476.00
$ 381.00
$ 381.00 - $ 381.00
$ 381.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 469.00
$ 469.00 - $ 469.00
$ 469.00
$ 376.00
$ 376.00 - $ 376.00
$ 376.00

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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$ 469.00
$ 469.00 - $ 469.00
$ 469.00
$ 376.00
$ 376.00 - $ 376.00
$ 376.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 658.00
$ 658.00 - $ 658.00
$ 658.00
$ 526.00
$ 526.00 - $ 526.00
$ 526.00

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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$ 658.00
$ 658.00 - $ 658.00
$ 658.00
$ 526.00
$ 526.00 - $ 526.00
$ 526.00
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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 %
$ 403.00
$ 403.00 - $ 403.00
$ 403.00
$ 323.00
$ 323.00 - $ 323.00
$ 323.00

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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$ 403.00
$ 403.00 - $ 403.00
$ 403.00
$ 323.00
$ 323.00 - $ 323.00
$ 323.00
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 520.00
$ 520.00 - $ 520.00
$ 520.00
$ 417.00
$ 417.00 - $ 417.00
$ 417.00

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...

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$ 520.00
$ 520.00 - $ 520.00
$ 520.00
$ 417.00
$ 417.00 - $ 417.00
$ 417.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 383.00
$ 383.00 - $ 383.00
$ 383.00
$ 307.00
$ 307.00 - $ 307.00
$ 307.00

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...

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$ 383.00
$ 383.00 - $ 383.00
$ 383.00
$ 307.00
$ 307.00 - $ 307.00
$ 307.00
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 %
$ 419.00
$ 419.00 - $ 419.00
$ 419.00
$ 335.00
$ 335.00 - $ 335.00
$ 335.00

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...

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$ 419.00
$ 419.00 - $ 419.00
$ 419.00
$ 335.00
$ 335.00 - $ 335.00
$ 335.00
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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 %
$ 529.00
$ 529.00 - $ 529.00
$ 529.00
$ 424.00
$ 424.00 - $ 424.00
$ 424.00

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...

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$ 529.00
$ 529.00 - $ 529.00
$ 529.00
$ 424.00
$ 424.00 - $ 424.00
$ 424.00
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 %
$ 458.00
$ 458.00 - $ 458.00
$ 458.00
$ 365.00
$ 365.00 - $ 365.00
$ 365.00

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...

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$ 458.00
$ 458.00 - $ 458.00
$ 458.00
$ 365.00
$ 365.00 - $ 365.00
$ 365.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 615.00
$ 615.00 - $ 615.00
$ 615.00
$ 492.00
$ 492.00 - $ 492.00
$ 492.00

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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$ 615.00
$ 615.00 - $ 615.00
$ 615.00
$ 492.00
$ 492.00 - $ 492.00
$ 492.00
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 585.00
$ 585.00 - $ 585.00
$ 585.00
$ 467.00
$ 467.00 - $ 467.00
$ 467.00

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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$ 585.00
$ 585.00 - $ 585.00
$ 585.00
$ 467.00
$ 467.00 - $ 467.00
$ 467.00
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 574.00
$ 574.00 - $ 574.00
$ 574.00
$ 460.00
$ 460.00 - $ 460.00
$ 460.00

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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$ 574.00
$ 574.00 - $ 574.00
$ 574.00
$ 460.00
$ 460.00 - $ 460.00
$ 460.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 567.00
$ 567.00 - $ 567.00
$ 567.00
$ 453.00
$ 453.00 - $ 453.00
$ 453.00

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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$ 567.00
$ 567.00 - $ 567.00
$ 567.00
$ 453.00
$ 453.00 - $ 453.00
$ 453.00
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 %
$ 780.00
$ 780.00 - $ 780.00
$ 780.00
$ 625.00
$ 625.00 - $ 625.00
$ 625.00

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 ...

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$ 780.00
$ 780.00 - $ 780.00
$ 780.00
$ 625.00
$ 625.00 - $ 625.00
$ 625.00
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 %
$ 780.00
$ 780.00 - $ 780.00
$ 780.00
$ 625.00
$ 625.00 - $ 625.00
$ 625.00

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 ...

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$ 780.00
$ 780.00 - $ 780.00
$ 780.00
$ 625.00
$ 625.00 - $ 625.00
$ 625.00
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 592.00
$ 592.00 - $ 592.00
$ 592.00
$ 474.00
$ 474.00 - $ 474.00
$ 474.00

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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$ 592.00
$ 592.00 - $ 592.00
$ 592.00
$ 474.00
$ 474.00 - $ 474.00
$ 474.00
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Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 533.00
$ 533.00 - $ 533.00
$ 533.00
$ 428.00
$ 428.00 - $ 428.00
$ 428.00

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 ...

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$ 533.00
$ 533.00 - $ 533.00
$ 533.00
$ 428.00
$ 428.00 - $ 428.00
$ 428.00
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 %
$ 551.00
$ 551.00 - $ 551.00
$ 551.00
$ 440.00
$ 440.00 - $ 440.00
$ 440.00

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 ...

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$ 551.00
$ 551.00 - $ 551.00
$ 551.00
$ 440.00
$ 440.00 - $ 440.00
$ 440.00
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
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$ 540.00
$ 540.00 - $ 540.00
$ 540.00
$ 431.00
$ 431.00 - $ 431.00
$ 431.00

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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$ 540.00
$ 540.00 - $ 540.00
$ 540.00
$ 431.00
$ 431.00 - $ 431.00
$ 431.00
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