Radio frequency interference (electro-magnetic interference) suppression filters and chokes, heat sinks, mains transformers and pulse transformers, electric testers for verification of the electromagnetic immunity of electric and electronic equipment by the generation of high voltage impulses such as electrostatic discharges, transients, surges, bursts and high frequency disturbances and automatic test systems for testing electrical and electronic products for safety, electromagnetic compatibility and functional performance; all included in Class 9.;