LEDS, With their many advantages including energy efficiency, longevity and controllability, are now playing an important role in most forms of lighting. There is excellent LED products available and solid state lighting technology is improving rapidly. However tests on LED products found in the marketplace indicate a wide variation in product quality and hoe effectively they may illuminate a space. Some lower quality LEDs sold may not provide sufficient light, may flicker when dimmed, change colour through life or fail prematurely.