EPCOS B66364 ETD 39/20/13 Coil Formers B66364 series ETD 39/20/13 coil formers from EPCOS are constructed from GFR polyterephthalate and are suitable for use with B66363 transformer ferrite cores. B66364 coil formers have 16 pins. They meet the UL 94 V-0 standard and have an insulation class of IEC 60085: B66364B: F. These coil formers meet the IEC 60068-2-20 standard for solderability and resistance to soldering heat.