It is an OS2 single-mode fiber (9-micron core) designed for fast Ethernet, fiber channel, gigabit Ethernet, data center, ATM, and other data applications typically involving longer distances. The cord is for simplex (one fiber) applications or to support nonstandard duplex widths. 100% end-face, IL & RL tested. Check each product page for other buying options. OS2 LC to LC Duplex Jumpers, Riser Rated (OFNR), each assembled with Corning SMF 9/125 micron core/cladding optical fibers. OS2 (9/125 Singlemode) - 9 micron core, 125 micron. OM3 LC to LC Fiber Patch Cable Multi-Packs 10Gb Multimode 50/125 Duplex jumper cords (10Gb up to 300 meters).