What do the numbers mean at the end of the Jessica Simpson hair extension line?

I know that are used to identify the color but there was a certain color I liked, the chocolate copper (R6/30H), I was wondering if I told the code to my hair stylist if she can use it to make the color. Or should I actually buy the extensions and say, make my hair this color? Thanks....What do the numbers mean at the end of the Jessica Simpson hair extension line?
Call your hairstylist and ask if they can mix the color for you, and if they say no than buy the extensions and they should be able to get it pretty close