Optical fiber is used as a medium for and because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because propagates through the fiber with much lower compared to electricity in electrical cables. This allows long distances to be spanned with few. Innerducts are installed in existing underground conduit systems to provide clean, continuous, low-friction paths for placing optical cables that have relatively low pulling tension limits. They provide a means for subdividing conventional that was originally designed for single, large-diameter metallic conductor cables into multiple channels for smaller optical cables. Innerducts are typically small-diameter, semi-flexible subducts. According to GR-356, there ar.