The Germ-Sleuthing Kit. Have fun while learning about how germs spread and the importance of proper handwashing. This easy-to-use kit provides safe interaction tools for demonstrating how easily harmful bacteria and viruses can transfer from one surface to another. Includes a germ-tracking blacklight, glow powder, and activity suggestions. Blacklight measures 3-3/8″ x 1″ and uses 3 AAA batteries. *Batteries not included.