Fiber optic patch cables are becoming more and more popular for light and data transmission in vacuum and ultra-high vacuum (UHV) environments. Under these conditions, fibers must only emit a minimum amount of gas to maintain the vacuum. During their assembly, UHV connectors made of SSL 304L steel are fixed with special vacuum-compatible adhesive processes. Bare fibers must be protected by a loose tube. FC connectors are most common in "normal" vacuum surroundings, but SMA 905 connectors are also available as an option; as are the fiber optic vacuum adapters and couplings through which the fibers are fed into the vacuum chambers.