This is a 20m ST (male) to ST (male) red duplex plenum-rated fiber patch cable. An OM3 cable has a core size of 50 microns that supports 10 Gigabit Ethernet at lengths measuring up to 300 meters, and 40 Gigabit or 100 Gigabit Ethernet measuring up to 100 meters. This plenum-rated cable is the only cable allowed in spaces defined as air plenum-rateds, such as raised flooring systems and air handling ducts. Plenum-rated cables must self-extinguish and prevent re-ignition. A duplex cable is a two-strand fiber optic patch cable that works best with transceivers that both transmit and receive. Our patch cables are 100% compliant for all of your networking needs. Our products are guaranteed by federal law to not affect or void OEM warranties.