TNC series connectors are similar to BNC connectors except for their mating threaded coupling which is designed to provide low reflection that operate from DC ~ 11 Ghz under extreme environmental conditions, especially shock and " vibration ." There are two types of TNC connectors : " Standard " and " Reverse Polarity ." Although TNC rugged design was initially developed for high vibration environments, TNC connectors are widely accepted and used in many applications.