This BNC crimp plug is a 75 ohm coaxial connector for RG59 cable, graded for commercial use.
BNC connectors use a bayonet coupling that locks with a quarter turn, which is why they remain common on coaxial video and CCTV runs where connections need to be made and remade without tools. This also makes them well suited to patching where a connector is changed frequently during testing or fault finding.
