Bulb Size and Bases. C7 bulbs are smaller than C9 bulbs by 1 inch. C7 bulbs are 2 inches long and C9 bulbs are 3 inches long. C7 bulbs sit in a base known as a candelabra base and can only fit in this specific type of base. C9 bulbs sit in a base known as an intermediate base.
Indoor cable. Indoor fiber optic cable normally includes tight buffer type, distribution cable, breakout cable and armored cable etc. Cable's job is to protect the fibers from the environment encountered in an installation.
Lets define our terms. Outside Plant (OSP) Telephone companies, CATV and the Internet all use lots of fiber optics, virtually all of which is singlemode fiber and most of which is outside buildings. It hangs from poles, is buried underground, pulled through conduit or is even submerged underwater.