Fiber optic communication has several military applications due to its advantages over traditional copper wire. It allows for repeaters every 16km compared to 500m for coax, is lighter weight, and has higher bandwidth for transmitting multiple signals. Fiber optic cables are also more secure as they are not affected by electromagnetic or radio frequency interference and are very difficult to tap. One weapon application is the FOG-M missile, which uses a fiber optic cable to transmit video feedback to the gunner for guidance. Fiber optics are also used for optical computing, military surveillance and sensors due to their ruggedness, and aboard vehicles since they are lighter and immune to electromagnetic interference.