VITROPERM® Common Mode Chokes Vacuumschmelze (VAC) VITROPERM® Common Mode Chokes are manufactured with a tape wound nanocrystalline material that offers a permeability range of 25,000 to over 100,000 when compared to ferrite permeability that ranges from 5000 to 15,000. VAC VITROPERM Common Mode Chokes offer several advantages, including small size, reduction of filter designs from two or three chokes to a single choke, high efficiency (low power loss due to less copper windings required), high operating temperature compared to ferrite, no operating noise, low weight and volume, better shock and vibration when compared to ferrite, and linear performance over temperature range. These chokes are suitable for high currents and/or high voltages.