Mundorf coils are made from highly thermally stressable wires and spool bodies in order to withstand the extreme loads occuring in professional audio use. Bobbins from glass fibre reinforced PA6.6 avoid the notorious deformations (melting and fracturing) of bobbins from ABS-plastics. Same time they allow a more stable and economic assembly compared to bodiless coils, which additionally transmit more kinetic energy into/from the PCB (Keyword: Microphonics).