This 275-watt self-ballasted bulb also produces heat. It is very important that you monitor the heat at the basking area and adjust the fixture-to-basking area distance accordingly to maintain a proper heat gradient. ALWAYS triple check the temperature at the basking spot - never risk burning your reptile. Mega-Ray SB 275-watt narrow-flood is a 275-watt Self Ballasted Par-38 True Frosted Flood Lamp. A true flood lamp, it will disperse usable UVB in a 30" circumference at a 34" distance. MINIMUM distance setting of 34" will produce approximately 150-200 microwatts per square centimeter (uW/cm2) of UVB and 900-1200uW/cm2 of UVA. MAXIMUM distance setting of 46" will produce approximately 50-75 microwatts per square centimeter (uW/cm2) of UVB. (Distance is measured from lamp face to basking spot or reptile for optimum UVB and heat.)