Sintermetalle Prometheus is specialized in production of (almost) lossless chokes for application in Power filters (high currents).
Vesta, one of the largest manufaturers of windmills in Europa, use these chokes throughout their productrange.
Losses in the chokes are decreased up to 75% which leads to an obvious increase in efficiency.
On their homepage you can find an overview of the possibilities.
These chokes can be custom-made starting from one piece upwards. Normally, samples are available in 2 weeks.

  Renewable energy  
  Vacuumschmelze (VAC)