The DIALIGHT 556 series indicator lights feature a flat lens design and are engineered for 1" mounting hole applications. Constructed with a nickel-plated brass housing, these lights provide durability and corrosion resistance. They are watertight, meeting NEMA 4X and IP66 standards, making them ideal for harsh environments. The 556-3205-304F model is particularly versatile, supporting various voltage inputs and offering clear visual indication for a range of industrial processes and equipment. Requires external resistor.