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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 %
$ 586.00
$ 586.00 - $ 586.00
$ 586.00
$ 469.00
$ 469.00 - $ 469.00
$ 469.00

Foster BLSC7-3, 1/4" Industrial Coupler x Reusable Hose Fitting, 5/16" ID x 5/8" OD, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BLSC7-3 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series ...

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$ 586.00
$ 586.00 - $ 586.00
$ 586.00
$ 469.00
$ 469.00 - $ 469.00
$ 469.00
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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 %
$ 588.00
$ 588.00 - $ 588.00
$ 588.00
$ 471.00
$ 471.00 - $ 471.00
$ 471.00

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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$ 588.00
$ 588.00 - $ 588.00
$ 588.00
$ 471.00
$ 471.00 - $ 471.00
$ 471.00
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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 %
$ 579.00
$ 579.00 - $ 579.00
$ 579.00
$ 463.00
$ 463.00 - $ 463.00
$ 463.00

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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$ 579.00
$ 579.00 - $ 579.00
$ 579.00
$ 463.00
$ 463.00 - $ 463.00
$ 463.00
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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 %
$ 581.00
$ 581.00 - $ 581.00
$ 581.00
$ 465.00
$ 465.00 - $ 465.00
$ 465.00

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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$ 581.00
$ 581.00 - $ 581.00
$ 581.00
$ 465.00
$ 465.00 - $ 465.00
$ 465.00
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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 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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$ 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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$ 410.00
$ 410.00 - $ 410.00
$ 410.00
$ 328.00
$ 328.00 - $ 328.00
$ 328.00

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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$ 410.00
$ 410.00 - $ 410.00
$ 410.00
$ 328.00
$ 328.00 - $ 328.00
$ 328.00
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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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$ 1,201.00
$ 1,201.00 - $ 1,201.00
$ 1,201.00
$ 960.00
$ 960.00 - $ 960.00
$ 960.00

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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$ 1,201.00
$ 1,201.00 - $ 1,201.00
$ 1,201.00
$ 960.00
$ 960.00 - $ 960.00
$ 960.00
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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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$ 1,131.00
$ 1,131.00 - $ 1,131.00
$ 1,131.00
$ 905.00
$ 905.00 - $ 905.00
$ 905.00

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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$ 1,131.00
$ 1,131.00 - $ 1,131.00
$ 1,131.00
$ 905.00
$ 905.00 - $ 905.00
$ 905.00
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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 %
$ 376.00
$ 376.00 - $ 376.00
$ 376.00
$ 301.00
$ 301.00 - $ 301.00
$ 301.00

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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$ 376.00
$ 376.00 - $ 376.00
$ 376.00
$ 301.00
$ 301.00 - $ 301.00
$ 301.00
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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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$ 348.00
$ 348.00 - $ 348.00
$ 348.00
$ 278.00
$ 278.00 - $ 278.00
$ 278.00

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 — ...

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$ 348.00
$ 348.00 - $ 348.00
$ 348.00
$ 278.00
$ 278.00 - $ 278.00
$ 278.00
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 %
$ 506.00
$ 506.00 - $ 506.00
$ 506.00
$ 405.00
$ 405.00 - $ 405.00
$ 405.00

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 — ...

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$ 506.00
$ 506.00 - $ 506.00
$ 506.00
$ 405.00
$ 405.00 - $ 405.00
$ 405.00
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 %
$ 394.00
$ 394.00 - $ 394.00
$ 394.00
$ 314.00
$ 314.00 - $ 314.00
$ 314.00

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 ...

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$ 394.00
$ 394.00 - $ 394.00
$ 394.00
$ 314.00
$ 314.00 - $ 314.00
$ 314.00
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 %
$ 376.00
$ 376.00 - $ 376.00
$ 376.00
$ 301.00
$ 301.00 - $ 301.00
$ 301.00

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 — ...

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$ 376.00
$ 376.00 - $ 376.00
$ 376.00
$ 301.00
$ 301.00 - $ 301.00
$ 301.00
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 %
$ 422.00
$ 422.00 - $ 422.00
$ 422.00
$ 339.00
$ 339.00 - $ 339.00
$ 339.00

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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$ 422.00
$ 422.00 - $ 422.00
$ 422.00
$ 339.00
$ 339.00 - $ 339.00
$ 339.00
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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 %
$ 1,956.00
$ 1,956.00 - $ 1,956.00
$ 1,956.00
$ 1,566.00
$ 1,566.00 - $ 1,566.00
$ 1,566.00

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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$ 1,956.00
$ 1,956.00 - $ 1,956.00
$ 1,956.00
$ 1,566.00
$ 1,566.00 - $ 1,566.00
$ 1,566.00
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 %
$ 469.00
$ 469.00 - $ 469.00
$ 469.00
$ 374.00
$ 374.00 - $ 374.00
$ 374.00

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 — ...

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$ 469.00
$ 469.00 - $ 469.00
$ 469.00
$ 374.00
$ 374.00 - $ 374.00
$ 374.00
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 %
$ 353.00
$ 353.00 - $ 353.00
$ 353.00
$ 282.00
$ 282.00 - $ 282.00
$ 282.00

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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$ 353.00
$ 353.00 - $ 353.00
$ 353.00
$ 282.00
$ 282.00 - $ 282.00
$ 282.00
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 %
$ 1,288.00
$ 1,288.00 - $ 1,288.00
$ 1,288.00
$ 1,030.00
$ 1,030.00 - $ 1,030.00
$ 1,030.00

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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$ 1,288.00
$ 1,288.00 - $ 1,288.00
$ 1,288.00
$ 1,030.00
$ 1,030.00 - $ 1,030.00
$ 1,030.00
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 %
$ 1,226.00
$ 1,226.00 - $ 1,226.00
$ 1,226.00
$ 982.00
$ 982.00 - $ 982.00
$ 982.00

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...

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$ 1,226.00
$ 1,226.00 - $ 1,226.00
$ 1,226.00
$ 982.00
$ 982.00 - $ 982.00
$ 982.00
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 %
$ 349.00
$ 349.00 - $ 349.00
$ 349.00
$ 280.00
$ 280.00 - $ 280.00
$ 280.00

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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$ 349.00
$ 349.00 - $ 349.00
$ 349.00
$ 280.00
$ 280.00 - $ 280.00
$ 280.00
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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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$ 316.00
$ 316.00 - $ 316.00
$ 316.00
$ 253.00
$ 253.00 - $ 253.00
$ 253.00

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 —...

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$ 316.00
$ 316.00 - $ 316.00
$ 316.00
$ 253.00
$ 253.00 - $ 253.00
$ 253.00
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 %
$ 280.00
$ 280.00 - $ 280.00
$ 280.00
$ 225.00
$ 225.00 - $ 225.00
$ 225.00

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...

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$ 280.00
$ 280.00 - $ 280.00
$ 280.00
$ 225.00
$ 225.00 - $ 225.00
$ 225.00
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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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$ 312.00
$ 312.00 - $ 312.00
$ 312.00
$ 250.00
$ 250.00 - $ 250.00
$ 250.00

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 —...

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$ 312.00
$ 312.00 - $ 312.00
$ 312.00
$ 250.00
$ 250.00 - $ 250.00
$ 250.00
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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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$ 305.00
$ 305.00 - $ 305.00
$ 305.00
$ 244.00
$ 244.00 - $ 244.00
$ 244.00

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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$ 305.00
$ 305.00 - $ 305.00
$ 305.00
$ 244.00
$ 244.00 - $ 244.00
$ 244.00
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