N Type RF Coaxial Connector
Telsto RF N-Type 50 Ohm connectors are durable, weatherproof, medium-sized units offering consistent performance through 11GHz.
The N connector (in full, Type N connector) is a threaded, weatherproof, medium-size RF connector used to join coaxial cables. It was one of the first connectors capable of carrying microwave-frequency signals, and was invented in the 1940s by Paul Neill of Bell Labs, after whom the connector is named. (From Wiki)