Martindale Proving Unit is a convenient pocket-sized, battery powered proving unit that produces a 240VDC output. Any device used for voltage detection and for proving dead should be tested before and after use to ensure the safety of the operative. The current is limited to 2mA and is suitable for use with multimeters and other voltage detectors that have an input impedance greater than 120k?. It has a long battery life and comes complete with a belt clip.