IEC 62317-2:2010 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of pot-cores made of ferrite, and the dimensional limits for coil formers to be used with them. The selection of core sizes for this standard is based on the philosophy of including those sizes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. See IEC 62317-1 for more detail concerning the philosophy of selecting core sizes to be included. This first edition cancels and replaces the fourth edition of IEC 60133 published in 2000. The main changes with respect to the previous edition of IEC 60133 are listed below: - changed 'e dimension' of P4,6/3,1 in Table 6 from 3,20 Max. to 3,40 Max.; - removed 'derived standards' from Annex B (informative) in the fourth edition of IEC 60133; - changed the name of core parts in Subclause 3.1.2 from 'Grooves' to 'Wire-ways' in accordance with IEC 62317-1 Subclause 5.6.