Bkl sma adaptors sma and rp sma gold plated contacts gold or nickel finish bkl 0419121 bkl electronics 0419121 this is an inline adaptor with a female reverse polarity sma connector to a bnc socket gold plated brass body with gold plated contacts reverse polarity sma refers to the mechanical arrangment rather than the electrical signals this connector has a central pin instead of a socket but still has an external thread bkl 0419121 sma adaptor sma reverse female to bnc socket gold plated