Bulova 9L and 10L

I found some Bulova parts boxes that are labeled 9L and 10L and inside they both have containers labeled "10AN" In other words, some containers say 9L 10AN and the others say 10L 10AN. What movement would a 9L 10AN be versus a 10L 10AN?
I know "L" stands for "Ligne" which represents movement diameter size...but what would be the difference between a 9L 10AN and 10L 10AN do you think? It has me baffled.....