... density, high curie temperature, low losses, low coercive force, low remenance.There are C-cores, toroidal cores. POWER TRANSFORMER CORES Item No Core size ... (mm) Case size(mm)AeS (cm2) Le L (cm) Frequency P(f=20KHz ... .85 6~8 IO120-70-30 120703012667355.2529.85 6~12 IO120-60-30 120603012557356.328.27 8~15 IO130-80 ...