Review on Alonefire SV18 - Rechargeable 12W UV Flashlight For Stain Detection & Resin Curing With Battery & Charging Indicator - Perfect For Scorpion & Pet Urine Detection by Duane Kaul

While the actual cold power is only 7 of the 12 Watts claimed, the light works well. Overrating of power and lumens, (which I didn't measure) is pretty typical for these sorts of imported devices. With a very narrow beam, a zoom would certainly be a nice feature. As others have observed, the center area is dimmer than the rest.The surprising news is that the battery actually exceeds its marked capacity at a measured 4.45 Ah. Sliding the battery into the housing is like pushing a cylinder into an air pump; very little clearance, but a smooth, easy, slide (at least on my unit). I tried a more standard 18650 cell in the flashlight and, besides wobbling around a little, it worked without issue.The button is not a direct connection to the LED. Rather, it goes thru a switching circuit. So, when unpowered, it doesn't remember the last state, but defaults to "off". The light functions even when a powered USB power cable is plugged in. While I wouldn't suggest leaving it on continuously, it probably could run that way.The LEDs under the push button are bright, evenly lit, and actually provide useful status information. Here's how they work under battery power:>3.0 V Green3.0 V Red<3.0 V Flashing Red<2.7 V Off (and power to the UV LED is switched off to protect the battery). Nice!