The OLED (Organic LED) Voltmeter is designed to withstand constant vibration and the rigors of a marine environment. Monitors voltage on a bright, waterproof, daylight readable OLED screen. High contrast and resolution make this screen visible from a wide viewing angle, even with polarized sunglasses. Reverse polarity protected. Constructed of injection molded nylon with terminal spade contacts. Fits Sea-Dog Power Socket Shell (4261001) and Mounting Bracket (4261051). IP66 rating.