The Lighting Arrester Model 392-SVSR2 is a two-pair gas tube lightning arrester in a plastic outdoor enclosure. It protects the communication lines that run between buildings against high voltage transients caused by motors, transmitters, lightning, etc. Transients can be harmful, and even capable of destroying building automation systems. It is recommended that the Model 392-SVSR2 be used at all points where communication cables exit or enter a building. To protect low voltage communications inputs on Building Automation Systems, this device should be used in conjunction with an appropriate voltage level surge protector such as a Model DTK-2LVLP.