Two Wire design.
High accuracy to meet most applications requirements.
With reverse polarity protection.

Display: 3 Digits LED
Measuring voltage range 4.5V-30.0V
Precision: 1%
Operating Current: less than 20mA
Input impedance> 100K ohms
Refresh speed of about 300mS 
Display Color: Red/Blue/Green
Operating temperature -10 ℃ ~ 65 ℃
Size: Approx. 48x29x22mm/1.81x1.14x0.87"

Dimensions: 48 x 29 x 22 mm(LxWxH)
Mounting hole: 46 x 27 mm
Net weight: 18g

Red wire:  +ve
Black wire:  -ve 

Package Includes:
1 x  LED Digital Voltmeter