Set the desired voltage ranges to safeguarding your appliances from low voltage dip and for high voltage surges. Adjustability ensures protections against harmful fluctuations.Choose a suitable current limit (1-140A) to prevent excessive current flows, effectively safeguarding both your equipment and living space. Tailors the protections to matching specific requirements.Stay inform about your electrical system health with the built-in voltage and current meter. Accurate measurements help identify potential issue early on, ensuring the safety and efficiency of your devices.Our circuit breakers offering stable and reliable performances. The current and voltage readings maintain an error margin of 5%, ensuring accurate monitoring and dependable protections.This instrument is only suitable for AC50-60Hz main power supply, and cannot be used for squarewave,otherwise the instrument will be permanently damaged!Specifications: Material:PlasticType:54VAHz/CH54VAMeasuring range: AC1-140A and AC50-500V.Auxiliary power supply: 50-500VACSize:Approx. 80x36x64mm/3.15x1.4x2.51inchInstallation mode: guide rail typeMeasurement accuracy: 0.5Display mode: LEDPackage Includes: 1x Under Voltage Relaysnote: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order.2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.