Designed for use with the Live Line Tester (LLT) MK2, the PH3 MK2 is a highly portable, battery powered unit for proving the live line testers function in the field. This proving unit produces a DC output voltage from a 9v PP3 battery source that lights up the red indicator when active. It is essential to prove that the Live Line Tester is functional both before and after testing the DC system to be worked on. The MK2 version has an integrated case that protects the unit when not in use. The wider base improves stability when using the unit in the field and also holds the operating instructions for added convenience and ease of use.