Astro 7764 Digital LCD Wide Range Circuit Tester 3-48V Computer Safe with Backlit 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 3-48 volt systems