Hi all, ok this totally confusing me I looked up my alloy style on real oem and it came up with

DescriptionSupplementQty From Up To Part NumberPriceNotes03Light alloy rim FRONT
9JX19 ET:482

36116761931$492.95+core03Light alloy rim EARF
10JX19 ET:452

36116761932$551.00+coreNow what does the 9J AND 10J refer to? is it the width in inches? thanks to all