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Foster 4 Series Couplers

The Foster 4 Series is the 3/8" body industrial interchange, one of the most common air coupler sizes for shop and industrial use. This collection includes 4 Series couplers and plugs in brass, steel, and stainless with NPT, hose barb, push-on, and reusable terminations. Filter by thread, material, and coupler or plug to match your line.

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€3,95 - €3,95
€3,95
€3,95 - €3,95
€3,95

Foster 40-4, 4 Series, Industrial Plug, 1/4" Male NPT, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 40-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

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€3,95 - €3,95
€3,95
€3,95 - €3,95
€3,95
€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95

Foster FM4204, 4 Series, Industrial Coupler, Automatic, 3/8" Female NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4204 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95
€4,95 - €4,95
€4,95
€4,95 - €4,95
€4,95

Foster 43-4, 4 Series, Industrial Plug, 3/8" Female NPT, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 43-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

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€4,95 - €4,95
€4,95
€4,95 - €4,95
€4,95
€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95

Foster FM4303, 4 Series, Industrial Coupler, Automatic, 3/8" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4304 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95
€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95

Foster 42-4B, 4 Series, Industrial Plug, 3/8" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 42-4B is a Brass 3/8" industrial plug from the Foster 4 Series — a high-fl...

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€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95
€3,95 - €3,95
€3,95
€3,95 - €3,95
€3,95

Foster 41-4, 4 Series, Industrial Plug, 1/4" Female NPT, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 41-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

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€3,95 - €3,95
€3,95
€3,95 - €3,95
€3,95
€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95

Foster FM4304, 4 Series, Industrial Coupler, Automatic, 3/8" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4304 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95
€16,95 - €16,95
€16,95
€16,95 - €16,95
€16,95

Foster 4004, 4 Series, Industrial Coupler, Manual, 1/4" Female NPT, Brass, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 4004 is a Brass/Steel 3/8" industrial coupler from the Foster 4 Series — a...

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€16,95 - €16,95
€16,95
€16,95 - €16,95
€16,95
€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95

Foster FM4004, 4 Series, Industrial Coupler, Automatic, 1/4" Female NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4004 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95
€17,95 - €17,95
€17,95
€17,95 - €17,95
€17,95

Foster 4204, 4 Series, Industrial Coupler, Manual, 3/8" Female NPT, Brass, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 4204 is a Brass/Steel 3/8" industrial coupler from the Foster 4 Series — a...

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€17,95 - €17,95
€17,95
€17,95 - €17,95
€17,95
€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95

Foster FM4404, 4 Series, Industrial Coupler, Automatic, 1/2" Female NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4404 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95
€5,95 - €5,95
€5,95
€5,95 - €5,95
€5,95

Foster 44-4, 4 Series, Industrial Plug, 1/2" Male NPT, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 44-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

View full details
€5,95 - €5,95
€5,95
€5,95 - €5,95
€5,95
€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95

Foster 45-4, 4 Series, Industrial Plug, 1/2" Female NPT, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 45-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

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€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95
€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95

Foster FM4804, 4 Series, Industrial Coupler, Automatic, 3/8" Hose Barb, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4804 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95
€7,95 - €7,95
€7,95
€7,95 - €7,95
€7,95

Foster 48-4B, 4 Series, Industrial Plug, 3/8" Hose Barb, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 48-4B is a Brass 3/8" industrial plug from the Foster 4 Series — a high-fl...

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€7,95 - €7,95
€7,95
€7,95 - €7,95
€7,95
€17,95 - €17,95
€17,95
€17,95 - €17,95
€17,95

Foster 4104, 4 Series, Industrial Coupler, Manual, 1/4" Male NPT, Brass, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 4104 is a Brass/Steel 3/8" industrial coupler from the Foster 4 Series — a...

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€17,95 - €17,95
€17,95
€17,95 - €17,95
€17,95
€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95

Foster FM4104, 4 Series, Industrial Coupler, Automatic, 1/4" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4104 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€22,95 - €22,95
€22,95
€22,95 - €22,95
€22,95
€24,95 - €24,95
€24,95
€24,95 - €24,95
€24,95

Foster FM1714, 4 Series, Industrial Coupler, Automatic, 3/8" Push-On Hose Barb, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM1714 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€24,95 - €24,95
€24,95
€24,95 - €24,95
€24,95
€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95

Foster 40-4B, 4 Series, Industrial Plug, 1/4" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 40-4B is a Brass 3/8" industrial plug from the Foster 4 Series — a high-fl...

View full details
€6,95 - €6,95
€6,95
€6,95 - €6,95
€6,95
€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95

Foster FM4504, 4 Series, Industrial Coupler, Automatic, 1/2" Male NPT, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4504 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95
€19,95 - €19,95
€19,95
€19,95 - €19,95
€19,95

Foster 4404, 4 Series, Industrial Coupler, Manual, 1/2" Female NPT, Brass, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 4404 is a Brass/Steel 3/8" industrial coupler from the Foster 4 Series — a...

View full details
€19,95 - €19,95
€19,95
€19,95 - €19,95
€19,95
€19,95 - €19,95
€19,95
€19,95 - €19,95
€19,95

Foster 4504, 4 Series, Industrial Coupler, Manual, 1/2" Male NPT, Brass, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 4504 is a Brass/Steel 3/8" industrial coupler from the Foster 4 Series — a...

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€19,95 - €19,95
€19,95
€19,95 - €19,95
€19,95
€4,95 - €4,95
€4,95
€4,95 - €4,95
€4,95

Foster 48-4, 4 Series, Industrial Plug, 3/8" Hose Barb, Steel

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster 48-4 is a Steel 3/8" industrial plug from the Foster 4 Series — a high-flo...

View full details
€4,95 - €4,95
€4,95
€4,95 - €4,95
€4,95
€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95

Foster FM4904, 4 Series, Industrial Coupler, Automatic, 1/2" Hose Barb, Brass

Reliable, leak-free 3/8" connections for air and fluid lines. The Foster FM4904 is a Brass 3/8" industrial coupler from the Foster 4 Series — a hig...

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€23,95 - €23,95
€23,95
€23,95 - €23,95
€23,95

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