Add a stylish touch to your terrarium while ensuring your reptile is receiving healthy levels of UVB. Zilla Rapid Sense UV Detecting Decor are unique pieces of decoration that help you maintain a healthy habitat for your reptile. Each piece of Zilla Rapid Sense UV Detecting Decor is equipped with a Rapid Sense indicator. When exposed to light the indicator changes color informing you of the UVB levels in the terrarium within 30 seconds. Reptiles need UVB to help synthesize vitamin D3 and maintain healthy calcium levels. Without enough UVB they?re in danger of developing nutritional diseases that can be fatal. With Zilla Rapid Sense UV Detecting Decor you can relax knowing you will recognize when it?s time to change the bulb. There are two designs to choose from depending on what look you want to go for the Poplar Log or the Crocodile Skull. Both designs provide spots for your pet to bask in the UVB light or hide if they need more privacy. They also include accents that fluoresce under a black light