Ultra Spec Cables 3M Multimode Simplex 40Gb OM4 Fiber Optic Patch Cable Cord (50/125) - FC to LCOur cables are manufactured using Corning Optical Fiber and OFNR Rated PVC jackets, which are lightweight, flexible and non flammable. Each cable is factory tested for insertion and return loss to ensure maximum performance and reliability. Fiber is preferred over copper because it provides increased bandwidth, low signal loss and is immune to interference. Fiber can carry data longer distances with more reliability and with less repeaters required.