Threaded FC/PC connectors are designed for high-vibration environments. It is commonly used with both single-mode optical fiber and polarization-maintaining optical fiber. FC connectors are used in datacom, telecommunications, measurement. This threaded nut FC connector features a one-piece design for quick termination, offering high mechanical and thermal resistance, making it ideal for secure fiber optic connections. Each type varies by shape, polish (APC, PC, or UPC), and return loss performance, which affect PC, UPC, and APC Polish Styles: What's the. Corning's FC-PC connectors (722 series) offer superior performance with very high repeatability.