BNC female to female coax couplers connector. These adapters have BNC female connector on both ends, and are constructed of nickel-plated brass with gold plated contacts.
These connectors will allow you to connect any CCTV Cable together and extend the lenght. 1 Coupler will be required for each cable that is extended. 
Package Includes

* (4) ACC-CN004-BNCF-BNCF BNC Female to BNC Female Connector