This 2AAA Mini-TAC UV light uses an Ultraviolet LED rated at 365 Nanometers for the purpose of detecting hidden security markings in documents, spotting leak detection fluids, and as an aid in visually locating proteins in forensics work. With a water-resistant design, it is constructed from aircraft-grade 6061-T6 aluminum with a Type II hard anodized finish. The tail switch provides momentary or constant-on functionality. The light comes with a removable pocket clip.  The MTU-106 is powered by two included AAA batteries.