The S & G Tool Aid Corp. Circuit Tester with Digital Display, No. 28300, measures 5V to 28V DC. The tester checks voltage, power, ground and circuitry without the need to hook up complex equipment. The display numbers are tall to make them easier to read, and a red LED indicates power while a green LED indicates ground. The lead wire stretches up to 11’ for use, then automatically retracts. The tester is computer safe and draws less than 10 milliamps at 12V. Components of each tester include a heavy duty ground clip with insulator and a sharp, stainless steel probe.