These lamps are low pressure mercury discharge lamps with tubular envelope of diameter T5 size. These lamps work only with HF electronic control gear. This lamp gives good color rendering, relatively high efficacy both initially and during lamp lifetime, with high lumen maintenance. These lamps deliver a rated life of 24000 hours. These lamps are available in following two categories: High Efficiency (14W and 28W) High Output ( 24W and 54W).