Ultra Spec Cables 1310nm Polarization-Insensitive Optical Isolator Cable, Single Stage, 900um Loose Tube, SC/UPC - 1 MeterUltra Spec Cables 1310nm Single Stage Optical Isolator Cable is used to safeguard light sources from signals and back reflections that can result in optical damage. Theyre designed to transmit light in the forward direction while deflecting or absorbing light generated in the reverse direction, which prohibits extraneous feedback into the system. The 900um jackets protect the inner fiber and the dust caps shield the end faces from contaminants that