GDT25-35-S1-BK is a next-generation 2-electrode gas discharge tube (GDT) surge arrestor designed for protection against induced voltage transients such as lightning and AC induction. The device features a DC sparkover voltage of 350 V (±20%) at 100 V/s, an impulse sparkover voltage of 650 V at 100 V/µs, and an insulation resistance greater than 2 GO at 1 kV/µs, with a DC holdover voltage of 135 V. It is housed in a compact 5 × 4.4 mm surface mount package (S1 designator) and operates reliably across a wide temperature range of -55°C to +125°C with low capacitance and minimal insertion loss. The GDT25-35-S1-BK is ideal for applications including set-top boxes, industrial communications, HVAC controls, xDSL/POTS/G.Fast systems, and antenna protection, where fast response time and high surge current rating are essential for protecting downstream components.