SMAKN&reg; 2 Wire Automatically Adjust Blue Dc 3.5-30v LED Panel Digital Display Voltage Meter Voltmeter Connection is simple, just need to pick up two lines, a joint reverse protection, then do not burn Starting voltage is low, only 3.50 V, can correct measurement Variable precision: Precision automatic change below 10.0 V, the highest resolution of 0.01 V, Prec Can be used for measuring the car / battery car / motorcycle battery voltage, and other forms of vol Can be used in all kinds of voltage measurement purposes