I carry it everywhere, but use it the least, the 375nm nichia Arc AAA UV. I got it for sterilization not forensics, but its far better at forensics, and I just pretend that I am killing microbes with it until I can have a much more powerful, custom (very $$$) 254nm (255) light built for me, and then that will be my least used light. But generally, I use all my lights all the time... carried on a spider keychain... effectively, I'm walking around with a chandolier. If the kids are reading this, please stop calling me "Gandalf." Nothing is wrong with me. Look at those idiots that still think digital watches are neat. What rubes.