Martindale hpat500 simple handheld pat tester martindale hpat500 p the martindale hpat500 is an easy to use battery powered hand held portable appliance tester pat tester with simple one button test selection its lightweight portable design makes it ideal for testing in all locations whether under a desk or testing a wall mounted monitor p p a single button press activates either a full class i class ii or lead test without any further interaction required by the user unless a