SMAKN&reg; 0.36" 12 Volt Battery Meter 3.0V-30V DC Auto Gauge Small Digital Voltmeter Blue LED Connection is simple, just need to pick up two lines, a joint reverse protection, then do not burn Starting voltage is low, only 3.2 V, can correct measurement Can be used in all kinds of voltage measurement purposes Can be used for measuring the car / battery car / motorcycle battery voltage, and other forms of vol This is the version with shell.