| + | Full-spectrum bulbs are sold with a numeric designation. 5.0 bulbs appear sufficient to stimulate the necessary previtamin D synthesis in lizards and are also considered suffifienct for snakes. Bulbs should be placed no further than 18 inches from the animal to ensure maximum UVB exposure. Glass refracts UVB radiation, and so glass lids are an inappropriate housing feature. Full-spectrum bulbs usually have an 8 to 14 month activity period. |