In addition to our standard product line, SFC KOENIG can provide custom expander plugs, flow restrictors and check valve parts as well as unique solutions specifically designed for your installation.

Our in-house engineering staff is available to assist you with your needs. With decades of expertise in sealing, we meet even the most unique requirements so your parts are produced and tailored to your exact application. Our team includes some of the industry’s most experienced engineers and manufacturing personnel. For that reason, we can deliver the solutions others cannot.

From material to size to operation, we are able to create custom expander plugs and flow control components to meet unique installations. We have become the leader in sealing and flow control with over 5 billion parts delivered to customers around the world, and we are ready to apply our knowledge to your exact order specifications.

SFC KOENIG maintains failure rates less than 1 part per million, delivering reliable solutions with unmatched consistency. Our engineering expertise, quality controls and efficient manufacturing operations are designed to produce the highest quality parts for each customer’s requirements.

SFC KOENIG brings more than 80 years of success to the design processes. From the initial design consultation to testing, production and process integration, we are ready to work with you to solve your unique sealing and flow control challenge.

Contact us today to review your design, and how a custom expander plug, flow restrictor or check valve solution can help achieve your goals.

  • Image of Custom Expander Plugs in Hydrogen Powered Bus
    SFC KOENIG engineers developed custom expander plugs for use in a hydrogen powered bus fleet.
  • Automotive Engine and Suspension System with Custom Flow Control Photo
    New engines and suspension system designs in automotive applications often require custom flow control components, such as those by SFC KOENIG.
  • Custom Expander Seal in EV Charging Photo
    Custom expander seals can block access to protect sensitive systems, such as in this EV charging port.


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SFC Koenig develops custom check valves, flow restrictors & check valves.

Installation Equipment

SFC KOENIG offers a complete line of installation equipment including hydropneumatic systems, handheld tools and setting components.


Our parts are proven reliable in a variety of industries and applications, including transportation, fluid power, precision and micro-hydraulics.