Review on DARKBEAM UV 395nm Flashlight USB Rechargeable: The Ultimate Portable Wood's Lamp with Black Light for Spotting Scorpions, Detecting Hidden Pet Urine, Resin Curing, and More! by Julie Parker

This UV flashlight is exactly what I was looking for - stylish design, made of high quality aluminum, rechargeable - and 18650 Li-ion battery that can be easily charged or replaced with a better one. The workmanship is good; All (threaded) parts fit well and smoothly. It has a telescopic lens function that allows you to narrow the beam. the gliding movement is smooth with the right resistance. Finally there is a clip on the side. Please note that the wavelength is 395nm, which means that the visible spectrum output is greater and slightly more energy efficient. They have the same design with a 365nm LED if that's what you're looking for. The light came with a proprietary Darkbeam battery which I suspect is a so-so unbranded battery - as expected at this price point. I didn't have time to measure the capacity, but I would probably extend the battery life of this flashlight by using a large capacity, low drain 18650 battery from a well known brand. It works well with the 18650 flat top as it uses spring pins on both ends.