Exo Terra Heat Emitter is a radiant heat source and creates a natural sun-like heat with a uniform pattern. The long wave infrared heat produced by this emitter will warm reptiles very efficiently. It also increases the ambient air-temperature in the terrarium. - Innovative design, 99% heat efficiency - Emits a natural "sun-like" infrared heat - No light emitted, does not disturb normal photo periods (day/night) - Solid ceramic element, suitable for humid environments Infrared heat penetrates the scales and skin tissue, promoting health and healing as it widens the blood vessels and increases blood circulation. All Sizes are 120 V - Available in 40, 60, 100, 150 and 250 Watt sizes. Dimensions (L x W (bottom of emitter)):60 Watt is 4" x 3"100 Watt is 4.5" x 3.5"150 Watt is 4.5" x 4"250 Watt is 4.5" x 5.5" Hagen Exo-Terra Exo Terra Heat Emitter: 100 Watt Ceramic Heater #PT2046 - Reptile Heat Bulbs - Habitat.