.The GSMD41-201M manufactured by Yenji is a gas discharge tube (GDT) surface mount device (SMD), measuring 2.8 x 5.0 mm and compliant with RoHS (Restriction of Hazardous Substances) regulations. It is a two-terminal arrester designed to protect electronic circuits from overvoltage caused by indirect lightning events. The GDT consists of a ceramic tube filled with a mixture of noble gases, a metal anode, and a metal telluride cathode. When the voltage exceeds the device’s max, an arc is created, resulting in equalization of the voltage and providing overvoltage protection to the electronics. This GDT has a 5KV maximum pulse surge protective voltage and an endurance of 20K surges.