This is a yellow bulk 1000 foot spool of fiber optic distribution cable intended for long distance runs at high speeds. It is composed of 2 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 Riser Rated (CMR) meaning it complies with UL-1666. It is for usage in vertical tray applications without environmental air. Examples being: cable runs between floors through cable risers or in elevator shafts. These cables self extinguish and prevent the flame from traveling up the cable in a vertical burn test. This fiber optic cable is solidly constructed, UL rated and RoHS Compliant.