The main difference is that Italy 7042 contains opening lubricant, and 7042N contains no opening lubricant. The n here is actually the abbreviation of the English word No, which means no, no.
The complete brands of 7042 and 7042N are: DFDA-7042 and DFDA-7042N. There are many kinds and brands of plastics. The difference between a letter or a number may actually represent a brand thousands of miles away. Therefore, it is best to provide a complete brand when forming a text description to avoid ambiguity.