Skip to content
☀️ Take an Additional 10% Off Your Entire Order with code GEARUP10 at checkout.
☀️ Additional 10% Off • GEARUP10

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.

Filters

Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95

Foster 3103H, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Heat/Viton, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3103H is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

View full details
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€9,95 - €9,95
€9,95
€9,95 - €9,95
€9,95

Foster 3103D, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Dill Valve, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3103D is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — ...

View full details
€9,95 - €9,95
€9,95
€9,95 - €9,95
€9,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95

Foster BL3103, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3103 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series —...

View full details
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€9,95 - €9,95
€9,95
€9,95 - €9,95
€9,95

Foster 3103, 1/4" Industrial Coupler x 1/4" Male NPT, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3103 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

View full details
€9,95 - €9,95
€9,95
€9,95 - €9,95
€9,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€54,95 - €54,95
€54,95
€54,95 - €54,95
€54,95

Foster BL2903S/S, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Ball Lock, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL2903S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Ser...

View full details
€54,95 - €54,95
€54,95
€54,95 - €54,95
€54,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€50,95 - €50,95
€50,95
€50,95 - €50,95
€50,95

Foster 2903S/S, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Serie...

View full details
€50,95 - €50,95
€50,95
€50,95 - €50,95
€50,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Foster 2903S, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Steam/EPDM, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903S is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — the...

View full details
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Foster 2903H, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Heat/Viton, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903H is a Steel 1/4" industrial coupler from the Foster 3 Series — the mo...

View full details
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€12,95 - €12,95
€12,95
€12,95 - €12,95
€12,95

Foster BL2903, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL2903 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series —...

View full details
€12,95 - €12,95
€12,95
€12,95 - €12,95
€12,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95

Foster 2903, 1/4" Industrial Coupler x 1/8" Male NPT, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 2903 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

View full details
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Foster 3203W, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — the...

View full details
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€47,95 - €47,95
€47,95
€47,95 - €47,95
€47,95

Foster 3203S/SLV, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Less Valve, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203S/SLV is a 303 Stainless 1/4" industrial coupler from the Foster 3 Ser...

View full details
€47,95 - €47,95
€47,95
€47,95 - €47,95
€47,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€50,95 - €50,95
€50,95
€50,95 - €50,95
€50,95

Foster BL3203S/S, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Ball Lock, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3203S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Ser...

View full details
€50,95 - €50,95
€50,95
€50,95 - €50,95
€50,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€46,95 - €46,95
€46,95
€46,95 - €46,95
€46,95

Foster 3203S/S, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Serie...

View full details
€46,95 - €46,95
€46,95
€46,95 - €46,95
€46,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95

Foster 3203LV, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Less Valve, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203LV is a Steel 1/4" industrial coupler from the Foster 3 Series — the m...

View full details
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95

Foster 3203H, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Heat/Viton, Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203H is a Steel 1/4" industrial coupler from the Foster 3 Series — the mo...

View full details
€11,95 - €11,95
€11,95
€11,95 - €11,95
€11,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€12,95 - €12,95
€12,95
€12,95 - €12,95
€12,95

Foster BL3203, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Ball Lock, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3203 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series —...

View full details
€12,95 - €12,95
€12,95
€12,95 - €12,95
€12,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95

Foster 3203, 1/4" Industrial Coupler x 3/8" Female NPT, 3 Series, Brass/Steel

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3203 is a Brass/Steel 1/4" industrial coupler from the Foster 3 Series — t...

View full details
€10,95 - €10,95
€10,95
€10,95 - €10,95
€10,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€16,95 - €16,95
€16,95
€16,95 - €16,95
€16,95

Foster BL3003W, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Ball Lock, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3003W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — t...

View full details
€16,95 - €16,95
€16,95
€16,95 - €16,95
€16,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Foster 3003W, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Water, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003W is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — the...

View full details
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€33,95 - €33,95
€33,95
€33,95 - €33,95
€33,95

Foster 3003S/SH, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Heat/Viton, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003S/SH is a 303 Stainless 1/4" industrial coupler from the Foster 3 Seri...

View full details
€33,95 - €33,95
€33,95
€33,95 - €33,95
€33,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€35,95 - €35,95
€35,95
€35,95 - €35,95
€35,95

Foster BL3003S/S, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Ball Lock, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster BL3003S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Ser...

View full details
€35,95 - €35,95
€35,95
€35,95 - €35,95
€35,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€31,95 - €31,95
€31,95
€31,95 - €31,95
€31,95

Foster 3003S/S, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, 303 Stainless

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003S/S is a 303 Stainless 1/4" industrial coupler from the Foster 3 Serie...

View full details
€31,95 - €31,95
€31,95
€31,95 - €31,95
€31,95
Foster BLH1B, 1/8" ISO-B Hydraulic Coupler x 1/8" Female NPT, ISO-B Series, Ball Lock, Brass
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Foster 3003S, 1/4" Industrial Coupler x 1/4" Female NPT, 3 Series, Steam/EPDM, Brass/SS

Reliable, leak-free 1/4" connections for air and fluid lines. The Foster 3003S is a Brass/SS 1/4" industrial coupler from the Foster 3 Series — the...

View full details
€13,95 - €13,95
€13,95
€13,95 - €13,95
€13,95

Request a Quote

Bulk and dealer pricing. Tell us what you need and we’ll reply within one business day.