How to Identify Carrier on z10 without opening the sealed box ?

Hi everyone, I recently win a z10 and i tried to find out from which carrier it may come from without opening the sealed box.
I'ved done some research but i couldn't find anything ! Here some info BB Z10 SLT100-3, 10.0.10 bundle 672, PRD-45184-012, Model RFK121LW. Thx in advance

Vito