Skip to content
Foster 6FFSDC, 1/4" FF Plus Socket Dust Cap, FF Plus Series, PVC

Foster K4S-101, 1/2" ISO-B Hydraulic Plug x 1/2" Female NPT, ISO-B Series, Viton Seal, Plated Steel

by Foster
Save 20% Save 20%
$ 476.00
$ 476.00 - $ 476.00
$ 476.00
$ 382.00
$ 382.00 - $ 382.00
$ 382.00

Reliable, leak-free hydraulic connections built to the most widely used industrial standard. The Foster K4S-101 is a plated steel 1/2" plug from the ISO-B Series (Foster FHK / Breco DS), compatible with ISO 7241-1 Series B couplings and rated to 5000 PSI. Valves in both halves shut off at disconnect to prevent fluid loss and air inclusion.

Specifications

  • Brand: Foster
  • Series: ISO-B (FHK / DS, ISO 7241-1 Series B)
  • Part Number: K4S-101
  • Interchange: 1/2" ISO 7241-1 Series B
  • Body: 1/2" Plug
  • Thread: 1/2" Female NPT, FPT
  • Type: Two-Way Shut-Off (both halves seal at disconnect)
  • Operation: Manual sleeve (retract to connect and disconnect at zero pressure)
  • Material: Plated Steel
  • Seal: Viton
  • Max Working Pressure: 5000 PSI
  • Vacuum Service: 27 in. Hg maximum
  • Standard: ANSI/B93.2, 4:1 safety factor
  • Quantity: 1pc
  • Origin: Made in USA

Why this plug

  • ISO 7241-1 Series B compatible — which means it couples with the industry-standard Series B interchange used across hydraulic equipment.
  • Two-way shut-off — which means both the socket and plug seal at disconnect, preventing oil loss and keeping contaminants out.
  • Connect/disconnect at zero pressure — which means safer operation and longer service life.
  • Hardened steel from solid bar stock — which means maximum resistance to hydraulic and mechanical shock for long life.
  • Viton (FKM) seal — which means compatibility with a wide range of fuels, oils, and chemicals at high temperature.

Frequently asked questions

What does this connect to?
It is compatible with ISO 7241-1 Series B couplings — the most common hydraulic interchange. Only same-size Series B sockets will couple.

What pressure is it rated for?
Rated to 5000 PSI maximum working pressure (coupled, non-shock, 4:1 safety factor).

Does it leak when disconnected?
No — the two-way shut-off seals both the socket and the plug at disconnect, preventing fluid loss.

Ideal for hydraulic power units, construction and agricultural equipment, and any line that must disconnect clean. Pair this plug with a matching 1/2" ISO 7241-1 Series B socket.

Why buy from hpcouplers: Foster quality, responsive US-based support, accurate specs, fast shipping.