Duplex fiber optic pigtail has two fibers and two connectors on one end. The connector end plugs into devices like transceivers or patch panels, while the bare end is typically fusion spliced to a fiber optic cable. The connector end is polished and tested under factory conditions, ensuring low insertion loss and high return loss. Unlike a patch cord, which has connectors on both ends, a pigtail features a factory-installed connector on one end and un-terminated fiber on the. Fiber Optic Pigtails, also known as pigtailed fibers, consist of an optical fiber connector and a section of optical cable.