OM1 LC/ST Plenum 62.5/125 Multimode Duplex Fiber Optic Patch Cables. OFNP multimode fiber (mmf) optical assembly with self-extinguishing plenum rated jacket, Corning 62.5/125um fiber core and terminated with small form factor 1.25mm ceramic ferrule LC connectors and 2.5mm stainless steel ferrule connectors.