I've the same question about my G20 that I've just received today and something just wasn't looking right... I just didn't knew what it was.
That being until I've noticed the different (round) side switch bezel and other small details...
Flashlight was bought from AliExpress: KLARUS G20 USB Rechargeable LED Flashlight 3000 Lumens LED Dual Switch Lantern LED Torch Flashlight Latarka Handheld Linterna
So... beware..
Side switch - round bezel, (instead of square with rounded corners) made of Aluminum (?), flush button cap instead of a convex shape, hollow cheap feel and kinda "wiggly"..
Anodizing - Looks more like paint and comes off quite easily, like... paint. Came with some small scratches from the get go. Just like it's the case with exfoliated paint on a badly prepared surface.
Tail switch - decent feel but kinda stiff and hard to press - wouldn't notice that if not looking for something, would probably just assume that it's the way it should be (idk... maybe it actually is.. :| )
Body battery compartment - about ~1.5mm of play between the battery and the body I'd say - Isn't that just a little bit excessive ? Idk..
Tail cap - so tightly fit that I wasn't able to unscrew it with all my force and the help of rubber pads and using some pliers (handles side) as leverage, squeezing as hard as I could
USB cable - looks cheap as chips as any other "5 at 1$ deals" made in China...
LED - Looks like an XHP70.2 while the original (?) should be using the older XHP70... :| (?)
Boost - lasts for 10 seconds sharp before stepping down, no matter what..
Font on head below the charging port - much bigger and plain different than the original seen everywhere on the internet sources, reviews, etc.
[EDIT]
Oh man... just realized... my G20 has 4 brightness levels AND Turbo.. So instead of Low 15LM, Mid 160LM, Hi 650LM and Turbo 3000LM, I have Low, Mid, Hi, Extra Hi (?) and Turbo :|
[/EDIT]
Ok, some pictures then.. ?