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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 %
$ 9.79
$ 9.79 - $ 9.79
$ 9.79
$ 7.79
$ 7.79 - $ 7.79
$ 7.79

Foster 12S-3, 1/4" Industrial Plug x 1/8" Male NPT, 3 Series, Free Swivel, Brass/Steel

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

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$ 9.79
$ 9.79 - $ 9.79
$ 9.79
$ 7.79
$ 7.79 - $ 7.79
$ 7.79
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 %
$ 4.59
$ 4.59 - $ 4.59
$ 4.59
$ 3.69
$ 3.69 - $ 3.69
$ 3.69

Foster 71-3, 1/4" Industrial Plug x 3/8" Push-On Hose Stem, 3 Series, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 71-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

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$ 4.59
$ 4.59 - $ 4.59
$ 4.59
$ 3.69
$ 3.69 - $ 3.69
$ 3.69
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 21% Save %
$ 5.19
$ 5.19 - $ 5.19
$ 5.19
$ 4.09
$ 4.09 - $ 4.09
$ 4.09

Foster 51-3, 1/4" Industrial Plug x 1/4" Push-On Hose Stem, 3 Series, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 51-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

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$ 5.19
$ 5.19 - $ 5.19
$ 5.19
$ 4.09
$ 4.09 - $ 4.09
$ 4.09
Save 21% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass Save 20% Save %
$ 44.59
$ 44.59 - $ 44.59
$ 44.59
$ 35.69
$ 35.69 - $ 35.69
$ 35.69

Foster 17-3S/S, 1/4" Industrial Plug x 3/8" Hose ID, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 17-3S/S is a 303 Stainless 1/4" industrial plug from the Foster 3 Series —...

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$ 44.59
$ 44.59 - $ 44.59
$ 44.59
$ 35.69
$ 35.69 - $ 35.69
$ 35.69
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 19% Save %
$ 7.29
$ 7.29 - $ 7.29
$ 7.29
$ 5.89
$ 5.89 - $ 5.89
$ 5.89

Foster 17-3B, 1/4" Industrial Plug x 3/8" Hose ID, 3 Series, Brass

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 ...

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$ 7.29
$ 7.29 - $ 7.29
$ 7.29
$ 5.89
$ 5.89 - $ 5.89
$ 5.89
Save 19% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 21% Save %
$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 2.99
$ 2.99 - $ 2.99
$ 2.99

Foster 17-3, 1/4" Industrial Plug x 3/8" Hose ID, 3 Series, Steel

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...

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$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 2.99
$ 2.99 - $ 2.99
$ 2.99
Save 21% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 8.49
$ 8.49 - $ 8.49
$ 8.49
$ 6.79
$ 6.79 - $ 6.79
$ 6.79

Foster 165-3, 1/4" Industrial Plug x 5/16" Hose ID, 3 Series, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 165-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most ...

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$ 8.49
$ 8.49 - $ 8.49
$ 8.49
$ 6.79
$ 6.79 - $ 6.79
$ 6.79
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 %
$ 7.99
$ 7.99 - $ 7.99
$ 7.99
$ 6.39
$ 6.39 - $ 6.39
$ 6.39

Foster 16-3B, 1/4" Industrial Plug x 1/4" Hose ID, 3 Series, Brass

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

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$ 7.99
$ 7.99 - $ 7.99
$ 7.99
$ 6.39
$ 6.39 - $ 6.39
$ 6.39
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 21% Save %
$ 3.39
$ 3.39 - $ 3.39
$ 3.39
$ 2.69
$ 2.69 - $ 2.69
$ 2.69

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

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...

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$ 3.39
$ 3.39 - $ 3.39
$ 3.39
$ 2.69
$ 2.69 - $ 2.69
$ 2.69
Save 21% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 11.59
$ 11.59 - $ 11.59
$ 11.59
$ 9.29
$ 9.29 - $ 9.29
$ 9.29

Foster 14-3GB, 1/4" Industrial Plug x 3/8" Male NPT, 3 Series, Ball Check, Brass

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 14-3GB is a Brass 1/4" industrial plug from the Foster 3 Series — the most...

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$ 11.59
$ 11.59 - $ 11.59
$ 11.59
$ 9.29
$ 9.29 - $ 9.29
$ 9.29
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 %
$ 9.39
$ 9.39 - $ 9.39
$ 9.39
$ 7.49
$ 7.49 - $ 7.49
$ 7.49

Foster 14-3B, 1/4" Industrial Plug x 3/8" Male NPT, 3 Series, Brass

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 14-3B is a Brass 1/4" industrial plug from the Foster 3 Series — the most ...

View full details
$ 9.39
$ 9.39 - $ 9.39
$ 9.39
$ 7.49
$ 7.49 - $ 7.49
$ 7.49
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 21% Save %
$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 2.99
$ 2.99 - $ 2.99
$ 2.99

Foster 14-3, 1/4" Industrial Plug x 3/8" Male NPT, 3 Series, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 14-3 is a Steel 1/4" industrial plug from the Foster 3 Series — the most p...

View full details
$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 2.99
$ 2.99 - $ 2.99
$ 2.99
Save 21% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 11.39
$ 11.39 - $ 11.39
$ 11.39
$ 9.09
$ 9.09 - $ 9.09
$ 9.09

Foster 10-3GS/S, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Ball Check, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 10-3GS/S is a 303 Stainless 1/4" industrial plug from the Foster 3 Series ...

View full details
$ 11.39
$ 11.39 - $ 11.39
$ 11.39
$ 9.09
$ 9.09 - $ 9.09
$ 9.09
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 %
$ 8.49
$ 8.49 - $ 8.49
$ 8.49
$ 6.79
$ 6.79 - $ 6.79
$ 6.79

Foster 10-3GS, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Ball Check, Steel

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

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$ 8.49
$ 8.49 - $ 8.49
$ 8.49
$ 6.79
$ 6.79 - $ 6.79
$ 6.79
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 19% Save %
$ 6.89
$ 6.89 - $ 6.89
$ 6.89
$ 5.59
$ 5.59 - $ 5.59
$ 5.59

Foster 10-3GB, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Ball Check, Brass

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

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$ 6.89
$ 6.89 - $ 6.89
$ 6.89
$ 5.59
$ 5.59 - $ 5.59
$ 5.59
Save 19% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 4.99
$ 4.99 - $ 4.99
$ 4.99
$ 3.99
$ 3.99 - $ 3.99
$ 3.99

Foster 10-3G, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Ball Check, Steel

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

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$ 4.99
$ 4.99 - $ 4.99
$ 4.99
$ 3.99
$ 3.99 - $ 3.99
$ 3.99
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 %
$ 17.29
$ 17.29 - $ 17.29
$ 17.29
$ 13.89
$ 13.89 - $ 13.89
$ 13.89

Foster 10-3DB, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Dill Valve, Brass

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

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$ 17.29
$ 17.29 - $ 17.29
$ 17.29
$ 13.89
$ 13.89 - $ 13.89
$ 13.89
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 %
$ 12.59
$ 12.59 - $ 12.59
$ 12.59
$ 10.09
$ 10.09 - $ 10.09
$ 10.09

Foster 10-3D, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, Dill Valve, Steel

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

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$ 12.59
$ 12.59 - $ 12.59
$ 12.59
$ 10.09
$ 10.09 - $ 10.09
$ 10.09
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 %
$ 9.49
$ 9.49 - $ 9.49
$ 9.49
$ 7.59
$ 7.59 - $ 7.59
$ 7.59

Foster 10-3S/S, 1/4" Industrial Plug x 1/4" Male NPT, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 10-3S/S is a 303 Stainless 1/4" industrial plug from the Foster 3 Series —...

View full details
$ 9.49
$ 9.49 - $ 9.49
$ 9.49
$ 7.59
$ 7.59 - $ 7.59
$ 7.59
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 18% Save %
$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 3.09
$ 3.09 - $ 3.09
$ 3.09

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

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
$ 3.79
$ 3.79 - $ 3.79
$ 3.79
$ 3.09
$ 3.09 - $ 3.09
$ 3.09
Save 18% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 21% Save %
$ 2.39
$ 2.39 - $ 2.39
$ 2.39
$ 1.89
$ 1.89 - $ 1.89
$ 1.89

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

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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$ 2.39
$ 2.39 - $ 2.39
$ 2.39
$ 1.89
$ 1.89 - $ 1.89
$ 1.89
Save 21% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 20% Save %
$ 12.49
$ 12.49 - $ 12.49
$ 12.49
$ 9.99
$ 9.99 - $ 9.99
$ 9.99

Foster 12-3S/S, 1/4" Industrial Plug x 1/8" Male NPT, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 12-3S/S is a 303 Stainless 1/4" industrial plug from the Foster 3 Series —...

View full details
$ 12.49
$ 12.49 - $ 12.49
$ 12.49
$ 9.99
$ 9.99 - $ 9.99
$ 9.99
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 %
$ 4.99
$ 4.99 - $ 4.99
$ 4.99
$ 3.99
$ 3.99 - $ 3.99
$ 3.99

Foster 12-3B, 1/4" Industrial Plug x 1/8" Male NPT, 3 Series, Brass

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

View full details
$ 4.99
$ 4.99 - $ 4.99
$ 4.99
$ 3.99
$ 3.99 - $ 3.99
$ 3.99
Save 20% Save %
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
Save 21% Save %
$ 2.89
$ 2.89 - $ 2.89
$ 2.89
$ 2.29
$ 2.29 - $ 2.29
$ 2.29

Foster 12-3, 1/4" Industrial Plug x 1/8" Male NPT, 3 Series, Steel

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
$ 2.89
$ 2.89 - $ 2.89
$ 2.89
$ 2.29
$ 2.29 - $ 2.29
$ 2.29
Save 21% Save %

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