The Stormtrooper costume has three levels of accuracy. You can see the requirements for all three levels in the CRL.
Level 2 is called Expert Infantry and level 3 is called Centurion.
These rockers are usually worn above the standard First Imperial Stormtrooper Detachment patch, and have the same width as that patch.
I have two versions of both rockers. They are more or less the same, but comes from different vendors.
I am Expert Infantry #767 and Centurion #358, after working hard to meet the requirements for both levels in October and November 2017.