Features:Through-hole design: no hardwiring difficulty. Measure the positive or negative current. There is no current restriction directionElectrically isolated from the high voltage power source, which eliminates the risk to delicate monitoring equipment and also minimizes safety concernsDisplay voltage or (+ -) current. Voltage range: 5V-120V. Current Range: 0-100A Wire Usage Ability: Hole diameter, through the sensor is 3/4 inch (19mm)Loop through the sensor multiple times to amplify the signal. For example, if your current signal is only 0.2 amps, you can loop the wire through the sensor 10 times, and the signal will be 10X stronger and appear as 2.0 ampsDescription:The hall effect current meter reads the current by detecting the magnetic field around the wire, there is no electric u, which eliminates the risk of delicate monitoring equipment, and also minimizes safety concerns. The sensor does not heat up, such as a current shunt resistor, which can have thermal temperature heat dissipation problems. Three display modes:1. Alternate between amplifiers and voltage2. Display only amplifiers3. Display Voltage OnlySpecifications:Measuring Range: +-100A Accuracy: +-1%Resolution: 0.3A Working Current: 7-15mA Power Supply: DC 5-120V Product Dimensions: 48mm*29mm*23mm Mounting Hole: 45.5mm*25.5mm Sensor Hole Diameter: 19mm Operating Temperature: -4°f-140°F (-20°c-60°C)Since the resolution is 0.3A, the current reading may flicker with 0.3A difference. For example, if the current is 1.7a, you can see 1.7a and 2.0a alternatively. This is normal. If your signal is too weak or you're not getting the resolution you want, you can coil the wire through the current sensor as many times as you want to double, triple, or quadruple the sensitivity or resolution. For example, if the current signal is only 0.2 amps, you can loop the wire through the sensor 10 times and the signal will be about 10X stronger and will appear as 2.0 amps. Note: We have more detailed manual, if you need electronic user manual, please sit down. Package Included:1x Digital Voltmete Ammeter1x Hall Sensor