Signal generators; Battery Testers; Active Equalizer being audio equalizer apparatus; Voltage modulation modules in the form of Adjustable High-Power Power Module; Power Amplifier Board for Audio Sound, namely, audio circuit boards

Ammeters; Tachometers; Transistors; Integrated circuit modules; pH meters; Power inverters; Step down transformers; Temperature sensors; Thermometers, not for medical purposes; Wireless transmitters and receivers