One-piece zero defect mechanical solutions


  • 100% tested and inspected
  • Zero leakage throughout the products lifecycle
  • No contamination or solvents
  • CAD files available to download



Permanent sealing of high and low pressure systems

Koenig Expanders are extremely resilient, permanently sealing holes and resisting pressures of up to 500 bar. The highest quality standards are maintained and certificated in-line with the demands of the automotive and hydraulics industry.

In traditional automotive applications, the Koenig Plug can be found in all applications where permanent metal-to-metal sealing is required and auxiliary holes have been drilled for oil, air, water or other gaseous or liquid mediums.

With simple hole preparation and a mechanical one-piece design, Expanders reduce waste in-terms of processes, machining and supplementary solvents and adhesives. The whole life cost of the Koenig Expander is substantially less than other component solutions due to installation integrity and ease, as well as zero defects in the field.

EV EDU Applications

  • Reduction gears
  • E-motors
  • Power inverter cooling systems
  • EDU housings and castings

ICE Applications

  • Clutch systems
  • Brake systems
  • Cylinder heads
  • Drivelines and shafts
  • Engine blocks
  • Emissions systems
  • Water pumps
  • Valve trains
  • Turbo chargers
Dual pipe exhaust on a blue car

100% leakproof sealing of drilled holes

Koenig expanders use leading expander technology to completely seal drilled holes without any waste, adhesives, or solvents. 5 billion units have been installed globally with failure rates below 1PPM. Expanders come in two types, suited for different applications.

Push type expanders

Push type expanders, Series MB and Series CV, are used to seal counterbored holes. Using a setting tool, the ball is pressed into the serrated sleeve, forming a complete metal-to-metal seal. Max. pressure of 450 Bar and sizes from 3 – 22 mm.

Pull type expanders

Pull type expanders, Series SKC and Series LK, are used to seal holes in difficult to access channels at angles or where holes are on different faces and the block cannot be moved. Pull type expanders use a mandrel to insert the plug into the hole. Pull type expansion plugs are ideal for high volume applications where rapid installation is required.

As the setting tool pulls the expander back into the hole, the plug expands and tightly seals the drilled hole. Max. pressure 500 Bar and sizes from 4 – 20 mm.


Row of engines being manufactured on a production line
Fuel Injection System distributing fuel through nozzles

precise control of fluid and gas

Koenig flow control solutions reliably regulate the flow of fluids and gasses at extreme pressures. The Koenig restrictor and Koenig Check valve combine SFC Koenig’s industry leading flow control technology and sealing expertise. Koenig flow control solutions leverage a one-piece mechanical design in a variety of sizes and pressure ratings for precise orifice flow control at low lifetime costs.


Koenig restrictors are designed for the accurate control of gas and fluid flow in deep-hole installations. Made from 300 series stainless steel with a one-piece mechanical expansion principle, they remain secure and reliable in high vibration applications. For full flow control, the Koenig flow restrictors orifice can be calculated to achieve your desired flow rates.

Check Valves

With a self contained ball style design and stainless steel material, Koenig ball check valves provide precise flow control with no leakage. Using the SFC Koenig expander technology they reliably regulate the flow of fluids under extreme pressure. Available in a range of sizes and opening pressures, in reverse and forward designs, Koenig one way check valves are effective at fluid flow control in many applications.


For more information on the Koenig range, to chat about an application or to request an engineer to call or visit, please don’t hesitate to call or fill out the below form.

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