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 + Blue; Display mode: Dual three 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: 14cm (Five wires); Measurement range: DC 0~999mA (current) 0~200V (voltage); Operation temperature: -10 degrees~65 degrees; Measurement accuracy: +/- (1% + 2words); 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)