The DG3R420M with Discharge Tubes (GDT/TSS) Axial,5x7.6mm RoHS is an electronic component manufactured by Dongchen. It is a type of gas-discharge tube (or gas tube) used to protect electrical circuits and components from overvoltage transients such as electrostatic discharges and power surges. It features a glass enclosure, axial leads, a 5x7.6 mm body, and is in compliance with RoHS restrictions. The tube works by releasing a spark when a certain voltage level is exceeded, diverting the current away from the sensitive device in order to provide overvoltage protection.