A broad spectrum daylight lamp for desert & tropical terrariums. The broad spectrum is ideal for plants photosynthesis & the UVA (ultraviolet A) light contributes to reptiles physiological well-being. Another important factor is the heat emitted by this bulb to increase the all over ambient temperature in the terrarium. Can be combined with Night Glo or Heat Glo for a 24-hour cycle. T10 available in 15 watt, 25 watt & 40 watt A19 available in 60 watt & 100 watt A21 available in 100watt & 150watt