Classification of specialized electronic components that protect circuits in manufacturing equipment and electronic devices from overvoltage, overcurrent, surge, and static electricity. Includes varistors, TVS diodes, gas discharge tubes, polyswitches, surge absorbers, ESD protectors, overcurrent protection ICs, voltage regulators, clamp diodes, and protection relays. These components protect critical electronic parts from lightning surges, power noise, electrostatic discharge, and short-circuit accidents in electronic control circuits of NC machine tools, industrial robots, automation equipment, control panels, inverters, and PLCs. Primarily handles industrial-grade protection components that operate reliably in harsh electrical environments of manufacturing sites.