Professional 3V-36V Digital LCD Automotive Circuit Tester with Polarity Indicator & Aluminum Alloy Handle. Universal Fit; Ideal for 12V/24V Fuse Box & Circuit Diagnostics. When diagnosing delicate computerized engine sensors (such as Camshaft, Crankshaft, or Hall-effect sensors) or high-speed LAN/CAN-bus communication lines, always use this digital high-impedance tester.