Tested in 10 habitats with both types of bulbs. The distance from the lamp to the beardie's head is about 15 inches. The lamps have no shielding between the UVB source and the reptile and the lamps are attached by reflectors. According to this gauge, the bulb must be lowered within 4 inches of the Beardie's head to get the correct UBI zone rating. Such a distance is dangerous. In any standard configuration, it's much better to buy a 6.2 model, which allows you to measure the wattage of a newβ¦