TAVR‑20 is a type of AVR (Automatic Voltage Regulator) unit. It lists specifications such as: 240 V AC ±10 %, input power, output, sensing input, response time, etc.It mentions an operating ambient temperature range of –20 °C to +70 °C for the unit.These sensors typically screw into the engine coolant jacket or oil line, detect temperature, give a voltage/resistance output to a controller which triggers shutdown or alarm.