EH Series, ST Fiber Optic Feedthru, Single-Mode - Nickel Finish. The EH Series by Switchcraft is a complete line of audio, video, and data connectors built into standard panel-mount XLR housings. Custom combinations of EH Series connectors can be quickly loaded into any of our Q-G Series panels. Once mounted, connecting your equipment to the back of an EH Series connector is fast and easy. Most connectors are feedthru, which means standard cabling is simply plugged into the back of your gear, then plugged into the back of the EH Series connector. For those EH Series connectors that are not feedthru, solder lugs are clearly marked for simple, secure solder connections. All EH Series connectors are available individually bagged with mounting screws.