The Mega-Ray mercury vapor bulb is our top-of-the-range 70 watt, 100 watt, 160 watt & 275 watt Self Ballasted Par-38 Narrow Flood Lamp in both 120 volt and 220-240 volt which has been shown in tests to produce similar amounts of UVB to natural sunlight! Along with adequate heat, the bulb creates a basking spot at the recommended distances in most circumstances. It promotes the synthesis of Vitamin D3 and prevents metabolic bone disease, and because of the very high levels of UVA, stimulates the emotional well being and activity. For 10 years, it has been shown to have the longest lasting UVB production of any other mercury vapor bulbs available.