Measure the Illuminance of White LED Lights. The LT40 LED light meter is useful for measuring and optimizing environmental light levels in a wide range of environments, including office buildings, manufacturing plants and warehouses, university campuses, schools, hospitals, and many other locations. OSHA regulates workplace lighting because illumination must be adequate for assigned tasks, and light meters are used to verify regulatory compliance, as well as state and local public safety codes and ordinances. Use of LED lighting is on the rise because it is more efficient to operate, it emits stable, high quality illumination, and the technology is dropping in price. Besides LED lighting, the LT40 can measure standard light sources fluorescent, metal halide, high pressure sodium and incandescent up to 400,000 lux (40,000 Fc). The LT40 comes with a built-in sensor with protective cover, 2 AAA batteries, storage pouch, and user manual.