Recommended usage is 5-20 seconds for optimum results.
The Aduro U-Clean Sanitizing Wand essentially works by using special bulbs that can emit the proper amount of UV-C light needed to kill bacteria on smooth surfaces. If you damage the DNA of the bacteria it dies, and if you damage the nucleic acid of the virus enough it cannot infect. Use it on your phone, desktop, keys, wallet, watch, or any surface.