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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 %
$ 32.99
$ 32.99 - $ 32.99
$ 32.99
$ 26.39
$ 26.39 - $ 26.39
$ 26.39

Foster SC7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 5/8" OD, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SC7-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

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$ 32.99
$ 32.99 - $ 32.99
$ 32.99
$ 26.39
$ 26.39 - $ 26.39
$ 26.39
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 %
$ 32.49
$ 32.49 - $ 32.49
$ 32.49
$ 25.99
$ 25.99 - $ 25.99
$ 25.99

Foster BLSC5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 9/16" OD, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSC5-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series ...

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$ 32.49
$ 32.49 - $ 32.49
$ 32.49
$ 25.99
$ 25.99 - $ 25.99
$ 25.99
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 %
$ 32.59
$ 32.59 - $ 32.59
$ 32.59
$ 26.09
$ 26.09 - $ 26.09
$ 26.09

Foster SC5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 9/16" OD, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SC5-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

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$ 32.59
$ 32.59 - $ 32.59
$ 32.59
$ 26.09
$ 26.09 - $ 26.09
$ 26.09
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 %
$ 26.69
$ 26.69 - $ 26.69
$ 26.69
$ 21.39
$ 21.39 - $ 21.39
$ 21.39

Foster BLSB7-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Ball Lock, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB7-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — ...

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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 %
$ 22.99
$ 22.99 - $ 22.99
$ 22.99
$ 18.39
$ 18.39 - $ 18.39
$ 18.39

Foster SB7-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB7-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — th...

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$ 22.99
$ 22.99 - $ 22.99
$ 22.99
$ 18.39
$ 18.39 - $ 18.39
$ 18.39
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 %
$ 67.39
$ 67.39 - $ 67.39
$ 67.39
$ 53.89
$ 53.89 - $ 53.89
$ 53.89

Foster BLSB7-3S/S, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Ball Lock, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB7-3S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Se...

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$ 67.39
$ 67.39 - $ 67.39
$ 67.39
$ 53.89
$ 53.89 - $ 53.89
$ 53.89
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 %
$ 63.49
$ 63.49 - $ 63.49
$ 63.49
$ 50.79
$ 50.79 - $ 50.79
$ 50.79

Foster SB7-3S/S, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB7-3S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Seri...

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$ 63.49
$ 63.49 - $ 63.49
$ 63.49
$ 50.79
$ 50.79 - $ 50.79
$ 50.79
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 %
$ 21.09
$ 21.09 - $ 21.09
$ 21.09
$ 16.89
$ 16.89 - $ 16.89
$ 16.89

Foster BLSB7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB7-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series ...

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$ 21.09
$ 21.09 - $ 21.09
$ 21.09
$ 16.89
$ 16.89 - $ 16.89
$ 16.89
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 %
$ 19.49
$ 19.49 - $ 19.49
$ 19.49
$ 15.59
$ 15.59 - $ 15.59
$ 15.59

Foster SB7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 5/8" OD, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB7-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

View full details
$ 19.49
$ 19.49 - $ 19.49
$ 19.49
$ 15.59
$ 15.59 - $ 15.59
$ 15.59
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 %
$ 28.39
$ 28.39 - $ 28.39
$ 28.39
$ 22.69
$ 22.69 - $ 22.69
$ 22.69

Foster BLSB5-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 9/16" OD, 3 Series, Ball Lock, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB5-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — ...

View full details
$ 28.39
$ 28.39 - $ 28.39
$ 28.39
$ 22.69
$ 22.69 - $ 22.69
$ 22.69
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 %
$ 22.09
$ 22.09 - $ 22.09
$ 22.09
$ 17.59
$ 17.59 - $ 17.59
$ 17.59

Foster BLSB5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 9/16" OD, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB5-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series ...

View full details
$ 22.09
$ 22.09 - $ 22.09
$ 22.09
$ 17.59
$ 17.59 - $ 17.59
$ 17.59
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 %
$ 21.09
$ 21.09 - $ 21.09
$ 21.09
$ 16.89
$ 16.89 - $ 16.89
$ 16.89

Foster SB5-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 9/16" OD, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB5-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

View full details
$ 21.09
$ 21.09 - $ 21.09
$ 21.09
$ 16.89
$ 16.89 - $ 16.89
$ 16.89
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 %
$ 23.69
$ 23.69 - $ 23.69
$ 23.69
$ 18.99
$ 18.99 - $ 18.99
$ 18.99

Foster SB3-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 1/2" OD, 3 Series, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB3-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — th...

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$ 23.69
$ 23.69 - $ 23.69
$ 23.69
$ 18.99
$ 18.99 - $ 18.99
$ 18.99
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 %
$ 109.79
$ 109.79 - $ 109.79
$ 109.79
$ 87.89
$ 87.89 - $ 87.89
$ 87.89

Foster SB3-3S/S, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 1/2" OD, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster SB3-3S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Seri...

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$ 109.79
$ 109.79 - $ 109.79
$ 109.79
$ 87.89
$ 87.89 - $ 87.89
$ 87.89
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 %
$ 26.29
$ 26.29 - $ 26.29
$ 26.29
$ 20.99
$ 20.99 - $ 20.99
$ 20.99

Foster BLSB3-3W, 1/4" Industrial Coupler x Reusable Hose Fitting, 1/4" ID x 1/2" OD, 3 Series, Ball Lock, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSB3-3W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — ...

View full details
$ 26.29
$ 26.29 - $ 26.29
$ 26.29
$ 20.99
$ 20.99 - $ 20.99
$ 20.99
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 %
$ 19.79
$ 19.79 - $ 19.79
$ 19.79
$ 15.79
$ 15.79 - $ 15.79
$ 15.79

Foster 3703W, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, Water, Brass/SS

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

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$ 19.79
$ 19.79 - $ 19.79
$ 19.79
$ 15.79
$ 15.79 - $ 15.79
$ 15.79
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 %
$ 72.29
$ 72.29 - $ 72.29
$ 72.29
$ 57.79
$ 57.79 - $ 57.79
$ 57.79

Foster BL3703S/S, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, Ball Lock, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3703S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Ser...

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$ 72.29
$ 72.29 - $ 72.29
$ 72.29
$ 57.79
$ 57.79 - $ 57.79
$ 57.79
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 %
$ 68.79
$ 68.79 - $ 68.79
$ 68.79
$ 55.09
$ 55.09 - $ 55.09
$ 55.09

Foster 3703S/S, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3703S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Serie...

View full details
$ 68.79
$ 68.79 - $ 68.79
$ 68.79
$ 55.09
$ 55.09 - $ 55.09
$ 55.09
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 %
$ 19.59
$ 19.59 - $ 19.59
$ 19.59
$ 15.69
$ 15.69 - $ 15.69
$ 15.69

Foster 3703S, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, Steam/EPDM, Brass/SS

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

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$ 19.59
$ 19.59 - $ 19.59
$ 19.59
$ 15.69
$ 15.69 - $ 15.69
$ 15.69
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 %
$ 17.69
$ 17.69 - $ 17.69
$ 17.69
$ 14.19
$ 14.19 - $ 14.19
$ 14.19

Foster BL3703, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3703 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series —...

View full details
$ 17.69
$ 17.69 - $ 17.69
$ 17.69
$ 14.19
$ 14.19 - $ 14.19
$ 14.19
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 %
$ 15.69
$ 15.69 - $ 15.69
$ 15.69
$ 12.59
$ 12.59 - $ 12.59
$ 12.59

Foster 3703, 1/4" Industrial Coupler x 3/8" Hose ID, 3 Series, Brass/Steel

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...

View full details
$ 15.69
$ 15.69 - $ 15.69
$ 15.69
$ 12.59
$ 12.59 - $ 12.59
$ 12.59
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 %
$ 17.49
$ 17.49 - $ 17.49
$ 17.49
$ 13.99
$ 13.99 - $ 13.99
$ 13.99

Foster BL3653, 1/4" Industrial Coupler x 5/16" Hose ID, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3653 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series —...

View full details
$ 17.49
$ 17.49 - $ 17.49
$ 17.49
$ 13.99
$ 13.99 - $ 13.99
$ 13.99
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 %
$ 17.09
$ 17.09 - $ 17.09
$ 17.09
$ 13.69
$ 13.69 - $ 13.69
$ 13.69

Foster 3653, 1/4" Industrial Coupler x 5/16" Hose ID, 3 Series, Brass/Steel

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

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$ 17.09
$ 17.09 - $ 17.09
$ 17.09
$ 13.69
$ 13.69 - $ 13.69
$ 13.69
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 %
$ 17.69
$ 17.69 - $ 17.69
$ 17.69
$ 14.19
$ 14.19 - $ 14.19
$ 14.19

Foster 3603W, 1/4" Industrial Coupler x 1/4" Hose ID, 3 Series, Water, Brass/SS

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

View full details
$ 17.69
$ 17.69 - $ 17.69
$ 17.69
$ 14.19
$ 14.19 - $ 14.19
$ 14.19
Save 20% Save %

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