SMA Female / TNC Female Low Loss RF Adapter
Common use for attaching Military handheld radio antennas to civilian handheld radios.
The TNC (Threaded Neill–Concelman) connector is a threaded version of the BNC connector. The connector has a 50 Ω impedance.
SMA (SubMiniature version A) connectors are semi-precision coaxial RF connectors developed in the 1960s as a minimal connector interface for coaxial cable with a screw-type coupling mechanism. The connector has a 50 Ω impedance.