The testo 745 non-contact Voltage Tester has a voltage range of up to 1,000 V AC. It is ideal for fast initial checking of any suspected fault sources. If an alternating current is present, the Voltage Tester will flash red and makes a corresponding warning sound. The Voltage Tester also has a filter for high-frequency interference signals therefore increasing its reliability. It is both waterproof and dustproof according to IP 67.