Charleston slave badge from 1820 for Servant No. 375

This is a square metal slave badge with clipped corners. On the recto is text that reads ”CHARLESTON [stamped]” across the top. Under that is “PORTER [stamped] / No. [stamped] 375 [punched] / 1820 [stamped].” On the verso is a stamped cartouche at the top center with the maker's name “LAFAR.” There is a hole punched at the center top.