A pigtail is a coiled or looped section of tubing used in piping and instrumentation systems to absorb vibration, manage thermal expansion, and protect pressure instruments from direct exposure to process media. A fiber optic pigtail is a short length of optical fiber —typically 0. The connector end is polished and tested under factory conditions, ensuring low insertion loss and high return loss. Moreover, its curved design allows it to flex under temperature or pressure changes. Indoor pigtails: The most common type. Lightweight, flexible, no extra protective layer. Designed for protected environments like splice trays inside ODF panels, fiber terminal boxes, and distribution frames. Not suitable for direct exposure to moisture, UV, or mechanical stress.