Review on ThruNite TT20 Rechargeable Flashlight, Momentary-On Tail Switch, High 2526 Lumens Bright Output Turbo Mode, USB C Rechargeable, 258 Meters Beam Distance, For Hunting, Hiking - Blue CW by Chris Pollreisz

I'll cut directly to the design flaw. The battery is bigger than 21700 it is more like a 21750 or 21800. Every other 21700 Li Ion battery I have is too short to work in the flashlight by about 5/16". I have a few manufactures of batteries such as Samsung and Molicel. So if you want a spare battery you will have to and get one from Thrunite for only 26$. That is ridiculous . I own a number of ThruNite flashlights and all spot on but this situation with their 21700 battery is a big time fail. What good is a agreed upon industry standard size requirement for a battery if it is not adhered to when designing a flashlight? The size difference for a bit more capacity is not worth not being able to use standard sized easily available 21700's already owned or trying to get another one of the the hybrid sized battery. I will be returning it. I don't feel like having to make a electrical contact spacer to take up the extra room. This also makes me think that any ThruNite flashlight that uses 21700's will also have the same problem. I don't like doing bad reviews but this isn't right at all.