The Hioki PD3129-10's non-contact voltage detection and measurement technology places efficiency and safety as priority considerations with the goal of protecting customers that need to conduct on-site electrical work as part of renovations and expansions of manufacturing plants and buildings. The Hioki PD312910 is a non-contact phase rotation meter that detects the phase of electrical current flow within insulated wires without using metallic contact voltage clips. The green arrow indicates normal phase, which can be useful for visual reports that document the proper completion of electrical work.