The S & G Tool Aid Corp. 12/24/42 Volt Circuit Tester, No. 28200, is for use on 12V and 24V, and 42V hybrid systems. The tester is computer-safe--it draws 3 milliamps at 12V. There are two LEDs for easy voltage-identification. The blue is for 12V and 24V, and the red for 42V. The wire has a heavy duty ground clip with insulator and stretches to 10' for use, then automatically retracts. The probe is super sharp.