This is a 40m 72xSC (male) to 72xSC (male) OFNR (Plenum-rated) fiber trunk cable. It is most commonly used for 100 Megabit Ethernet applications. 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.