The Martindale PD440S 440V AC Proving Unit is a reliable and efficient testing device designed for industrial use. With a unit quantity of 1, this product is essential for ensuring the quality and functionality of electrical systems. The Martindale brand is known for its durability and accuracy, making this proving unit a valuable asset to any business or industrial setting. Ideal for measuring and inspecting AC power distribution, this unit provides precise and dependable results for a range of applications.