Astro 7763 Digital LCD 12-24V Circuit Tester Clear LCD display for accurate voltage readouts Testers ground cable attaches to any ground while tester measures voltage from positive sources, or flip internal display to perform the opposite For use on cars, boats, trailers, vans, RV's, motorcycles, airplanes and snowmobiles Needle-sharp stainless steel probe allows for easy piercing Use to check electrical circuits and accessories on all 12~24 volt systems