Testboy-Digital-Insulation-Tester-Testboy-Testboy-TV-430N-P-The-Testboy-TV-430-is-a-Digital-Insulation-Measuring-Instrument-that-makes-it-possible-to-check-the-insulation-resistance-of-devices-electrical-systems-&-circuits-It-has-three-selectable-test-voltages-250-500-&-1000V-DC-P-P-A-continuity-tester-&-an-AC-voltmeter-have-also-been-integrated-to-round-off-the-options-for-use-in-a-wide-variety-of-applications-The-most-important-aspect-when-measuring-insulation-resistance-is-t