Typically these adapters are used by CCTV equipment.
Can be used to connect CCTV camera to TV, VCR or DVR, use regular RCA cables
BNC Female To RCA Male Plug Coax Adapter Connector
BNC locking mechanism designed for the easiest, highest quality connection
Suitable for converting a phono plug connection to a BNC plug. Useful for connection to CCTV monitors and to older video equipment which uses BNC connectors. Use of this adapter converts the BNC video input or output to a phono connection.