Pros: Durability, Battery Life, None
Good for checking for nasties when travelling
Always in my travel kit. Use for inspecting the hotel bathroom and other areas (TV remote, phone, light switches, door knobs, glass, etc.) for traces of stuff you never want to touch. Downside is it's not very powerful so you need to get up close, and in pretty much total darkness. Get the Covert version to have the beam more concentrated. Also, since the light beam is invisible, it's easy to forget to turn off, and it's soon dead.