GEREE 0.56'' DC 3.2-30V Digital Voltmeter Voltage Tester Gauge Red Bright LED Display Volt Meter Panel Meter High accuracy: Its decimal point will automatically move, and It also has a tiny potentiometer to do finer adjustments. Small size (48 x 29 x 22 mm) and wide voltage measuring range (DC3.2-30V). Two- wire connection, simple and convenient. High accuracy: +/- (1% +1 digit). The meter requires no extra power supply, meaning the tested voltage could work as a power supply. GEREE 12 Volt Digital Voltmeter warranty--30-Day Money Back Guarantee -- 12 Month Replacement Warranty -- Lifetime Support Guarantee