Features: brand new and high quality Product input voltage: 12-24V. Power outlet input voltage:dc 12-24v,rated output power:12V 15A 24V 10A. USB input:dc 12-24v,output:5V 4.8A(2.4A+2.4A)/5V 3.1A(2.1A+1A). Voltmeter measuring range: for DC 2.5-30V.(The for DC voltmeter monitors the voltage of the battery in real for time, and can judge whether the battery is charging according to the voltage.) Connection method: the red wire is connected to the positive pole of the power supply (12-24V+) the black wire is connected to the negative pole. Installation method: Open the hole to install about 172x40mm, then put it in the product, and fix it with screws. Specifications: Material:ABS Type:A,B Size:Approx.21x10.7x5cm/8.27x4.21x1.97in Net Weight:190g Note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Digtal Voltmeter