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Worldwide the KOENIG-EXPANDER® is the world leader solution for quick and reliable sealing of drilled holes.


  • Process reliability in installation
  • Save time setting up
  • Expander types in different materials
  • Available for the widest possible range of applications


Extremely versatile and available in a variety of materials the KOENIG-EXPANDER® permanently resists even the most extreme loads and pressures. Originally designed for use in hydraulic assemblies, it is now well established in all industries as a component in engines, gearboxes and transmissions, suspensions and braking systems, as well as in steering and fuel injection systems.




Pressure to 450 bar

Expansion and anchorage of sleeve in hole wall is achieved by pressing the ball into the sleeve. The MB series plugs are designed for use in base materials of both low to high hardness (up to 450 bar pressure).


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CV series

Pressure to 450 bar

The CV Expander plugs are available in different materials and surface treatments. The CV plugs are available in metric as well as Inch sizes. Expansion and anchorage of sleeve in hole wall is achieved by pressing the ball into the sleeve.

Advantages MB/CV series:

  • Operating pressures up to 450 bar / 6500 psi
  • Great range supplied from 3 – 22 mm also available in inch sizes
  • Corrosion-resistant version
  • Available in aluminium
  • Normal working tolerance 0 -+0,1 mm
  • Quick and easy to install
  • Purely mechanical seal due to forced interlocking


Pressure to 60 bar

The LK Series KOENIG-EXPANDERS® are ideal for lower pressures (max 60 bar) and use the tension/expansion concept. After reaching the sufficient force, the expanding element automatically breaks off at the predetermined breaking point. > Product search

SK series

Pressure to 500 bar

The tension/expansion concept of the SK series causes breaking off of the expanding element after reaching the predetermined force. These are particularly suitable for use in light metals, high pressure applications (up to max 500 bar), and also for bore holes with a smoother surface finish. > Product search

Installation equipment

For installing the SK, HK and LK series there are simple lever shears and various hydro-pneumatic hand tools available. Here too the quantity will be critical in deciding the method used. > Product search

LP series

Pressure to 60 bar 

The press fit and anchoring concept of the LP series makes use of a conical press-in sleeve. During installation, this adapts to the bore, and the outer serration bites into the bore wall. Particularly suitable for lower pressures (max 60 bar). > Product search