Astrodyne cord sets are UL rated and compliant with IEC Standard  60320. All cord sets have a specified temperature rating, current capacity and UL Classification I or II (some are not rated). Class I is a three-conductor cord with ground while Class II  specifies a two-conductor plug without ground.*

Each socket in the cord set  has an odd number and the power supply inlet is the next highest number.  Ex: IEC60320-C13  mates with an IEC60320-C14 inlet. See the following table for all sockets and inlets criteria in the IEC Connectors and Inlets Standard.