You are viewing the Sylvania F36w/172 Activa Fluorescent Tube – 0002219 which comes in the colour natural daylight. These tubes are also known as SAD fluorescent tubes. SAD also known as Seasonal Affective Disorder which is a form of depression commonly associated with lack of exposure to sunlight during winter months. SAD fluorescent tubes bring the benefits of the Sun indoors. The product comes with an average lamp life of 14,000 hours to give the customer peace of mind.