UVB lighting gives reptiles the ultraviolet they need to make vitamin D3 and use calcium properly, supporting strong bones and overall health. T5 UVB tubes and kits spread light evenly across the enclosure, and the right choice depends on your species, its natural light exposure and the distance from the lamp to the basking area. For best results, pair UVB with a basking lamp and full spectrum LEDs, replace tubes as the manufacturer recommends, and set everything on a timer to keep a consistent day and night cycle.