IEC 63093-3:2020 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of half pot-cores made of ferrite, intended to be used in inductive proximity switches. Half pot-cores for inductive proximity switches are also called PS-cores. The selection of core sizes and shapes for this document is based on the philosophy of including those sizes and shapes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. This part of IEC 63093 can also be considered as a sectional specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. It provides guidelines on the allowable limits of surface irregularities applicable to PS-cores in accordance with the relevant generic specification. This first edition cancels and replaces the first edition of IEC 62323, published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition of IEC 62323: a) addition of the limits surface irregularities.