Verilux 36 Watt linear compact fluorescent bulb provides pure white light that increases contrast & clarity, for better vision, while reduced glare and eyestrain make reading and other close-up tasks easier and more comfortable. Electronic ballast for instant-on with no flickering. Perfect for reading, sewing & crafts, especially for older eyes. Developed to reduce eyestrain by Howard Scott, founder of Verilux in 1956.This Verilux 36 Watt Natural Spectrum Replacement Bulb is energy efficient, long lasting, and produces a bright, white light similar to natural daylight. This bulb features a proprietary blend of rare earth phosphors, Trucolite Phosphor Technology, that filters out any imbalance in the light spectrum, increasing contrast and reducing glare compared to standard incandescent or fluorescent lighting. Genuine replacement bulb, to fit the Verilux/Satco HappyLite HPLD only.