DC Digital AmmeterDisplays amperage from -500 to +500 Amps 3 levels of display brightness Splashproof front Manual sleep mode blanks display for power conservation Standard meter operates in negative side of circuit only. Shunt Shifter required for positive side installation such as alternators Includes 500 Amp shunt Applicable for 12, 24, 32, 36, and 42 Volt DC systems WARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.