Features:  High precision: 4-digital.  Working voltage: DC 4V-28V.  Working current: <20mA.  Display: 0.28" Red + Blue Dual LED Display.  Voltage Measuring Range: DC 0.000V-100.0V.  Current Measuring Range: 0-9.999A.  Refresh rate: about 1S / 3times.  Operating temperature: -10°C - 65°C.  Working pressure: 80 to 106 kPa.  Size: 48x29x20 mm.  Mounting hole: 46 x 27 mm.  Current: Range x 0.08%+Two decimal point.  Voltage: Range x 0.08%+Two decimal point.     Wiring:  Red line thin: power supply +.  Red line (thick): IN+, current input.  Yellow line (thick): PW+, measuring terminal voltage input positive.  Black line thick: COM, common measuring.     Note:  Please follow the wiring diagram, special attention, the load can only be connected to the positive, not negative Otherwise burn the table      Package Included:  3 x DC 100V 10A 0.28 Inch Mini Digital Voltmeter Ammeter