The 5678181221 is a 78 pot core set manufactured by Fair-Rite Products, designed for use in all types of inductive devices requiring high self-shielding and magnetic design flexibility. The core features a center post that can be gapped to a mechanical dimension or A value, facilitating customization for various magnetic applications. Key electrical properties include an inductance factor (Al) of 2600 nH (±25%), an effective cross-sectional area (Ae) of 0.43 cm², an effective path length (le) of 2.59 cm, and an effective core volume (Ve) of 1.12 cm³. The dimensional specifications include an outer diameter (A) of 18 mm, a height (C) of 13.4 mm, and a center post diameter (D) of 3.8 mm, with the complete set weighing 6.0 grams. This pot core configuration is ideal for power supply inductors, EMI filters, and other magnetic circuit applications where compact size and integrated shielding are advantageous.