The Zero Ohm Coil (ZOC) is a transformer sized coil. It is made of Feron, a high quality material that limits the induced distortion to a maximum. In the ZOC, the center space is calibrated and adjusted by hand between the two laminar cores (one L-shaped, one E-shaped). The volume of the center gap determines the inductance of the coil and requires great care in the manufacturing process. It must not be too thin, otherwise saturation effects could occur at high load. These coils are recommended for filtering bass speakers. Their low impedance allows to improve the impulse response (better speaker behaviour).