Complex sentence: IEC 60320-2-1 specifies couplers, not interchangeable with other 60320 couplers, for use with household sewing machines, rated no higher than 2.5 amperes and 250 volts.
Split into simpler sentences: IEC 60320-2-1 specifies couplers, not interchangeable with other couplers from the standard, for use with household sewing machines. They are rated no higher than 2.5 amperes and 250 volts.