This is a yellow bulk 1000 foot spool of plenum fiber optic distribution cable intended for long distance runs at high speeds. It is composed of 6 singlemode fibers (9 micron core) inside an Aramid yarn wrapped in a yellow PVC outer jacket. Single mode fiber is optimized to work with fiber optic equipment using light wave lengths of 1310nm (nanometers) or 1550nm. The cladding diameter is 125 microns. The core and cladding of our yellow bulk distribution fiber optic cable is constructed using a high quality singlemode fiber that is ITU-T G.652.D compliant and backwards compatible with other legacy singlemode fibers. This particular cable is Plenum Rated. Plenum spaces are the area between floors or above office areas for heating/cooling airflow. If an office were to catch fire, this plenum area could easily allow the spread of the fire to more floors or across the entire building. Plenum rated cables are jacketed with a fire-retardant plastic jacket of either a low-smoke polyvinyl chloride (PVC) or a fluorinated ethylene polymer (FEP) for less toxicity during a fire.