State of the art carbon fiber heating technology radiates infrared waves creating uniform heating with not hot spots. Carbon fiber is an energy-efficient method for heating with no wires that might become pinched or broken and create a safety hazard. This safe and efficient material regulates itself to a maximum safe temperature of 113F without a sensitive thermal switch which can fail causing overheating. Each unit has an adhesive backing to keep it in contact with the tank for optimum heat transfer. Helps reptiles thromo-regulate for daily activity, appetite and metabolism Easy-to-use adhesive mounting for optimal heat transfer Energy-efficient external heat source Ideal heat source for desert and tropical species of reptiles, amphibians and arachnids Material self regulates and reaches a temperature of 113°F Available Sizes: Mini: 4.375 x 1.25 x 8.5", 4W (Fits Terrarium Size: 1-5 gallon) Small: 6.375 x 1.25 x 9.25", 8W (Fits Terrarium Size: 10-20 gallon) Medium: 7 x 1.25 x 13.25", 16W (Fits Terrarium Size: 30-40 gallon)