The P0300SB is a Gas Discharge Tube (GDT) SMB (DO-214AA) RoHS manufactured by SEMIWARE. It is a three-lead, surface mounted device made from a glass or porcelain body. It is designed to protect sensitive electronic equipment from overvoltage surges and electrical overstress. The GDT is triggered by an overvoltage surge, allowing the current to be diverted away from the equipment and preventing damage. This GDT meets the requirements of the Restriction of Hazardous Substances (RoHS) Directive, ensuring that there are no hazardous substances in its construction. It is widely used in consumer electronics, communication equipment, industrial control systems, LED lighting, and other fields.