Features: Perfect functions in one set of voltage meter measuring current power from the measuring circuit no separate power supply isolated power supply easy to use. Technical Parameters: Display color: Red + Green Display mode: Dual 3-digit 0.28 LED digital tube Update rate: About 500 ms/time Physical size: 48 x 29 x 26 mm (L x W x H) Opening size: 45 x 26 mm (L x W) Supply voltage: 3.5-30V Lead wire length: 14 cm (Five wires) Measurement range: DC 0-999mA (current) 0-200V (voltage) Operation temperature: -10 degrees~65 degrees Measurement accuracy: ± (1% + 2 words) Instruction of wiring Red thin wire (VCC):Power input+ 3.5-30V(NOTE: If the measuring signal is lower than 30V and have abundant power supply it can be used as power supply for the module [black wire and yellow wire are contacted together to use]) Black thin wire(GND):Power input- Measurement signal - 3.5-30V Yellow thin wire (VIN):Measurement signal+ (0-200V) Red thick wire (I+): Current input+ (connect with load negative) Black thin wire(I-): Current input- (in series in power supply negative)