It seems something like this:
https://www.google.pt/search?q=divot+tool&oq=divot+tool&aqs=chrome..69i57j0l5.3286j1j9&sourceid=chrome&ie=UTF-8
Some flashlight manufactures ( Prometheus or Malihini) use some custom tools to (un)screw the modules that make that “divot” effect:
Those are customized tools, but we, budget people, use nose pliers 
(at least I do 
)
Think leave well enough alone rather than risking scraping the surface. Thanks for the pics.
What emitters did you get in the D4Svn? If you got Samsungs its no wonder its green.
I have an E05 and its a nice light, but mine has a donut hotspot that seems to be driving me nuts.
I know the Samsung 351 are green too. The D4Svn are just 2 XPG2 PDT and 2 XPL-HI. The XPL-HIs keep it from being any worse but it’s a bad combo as it is. I’ve bought three Skylumen lights this year, no more though … they all had issues and disappointing and pricy.
I don’t have a hole in my Wuben E05, just not clean like you see in the photo. Looks good on the hand tho!
Well thats not good to hear. I just ordered a Toolvn with a XP-L HI so hopefully that does alright.
teacher, yeah I do want to produce my own light someday and really be paid for fun. Got to put my degree to ” real good ” use other than Engineering for someone else.
I posted this on the other review thread, thought It might be useful in this thread also.
.
I just tested my wuben E05 from amazon in my maukka lights calibrated Lumen Tube and got 900 lumens at turn on from the wuben 14500 and the same number from a efest 14500 out the front.
It does do 900 lumens out the front for at least for a second, I got 802 lumens at the 30 second mark. Nice to see a manufacture that list honest lumen numbers. 
Very nice well built light in my opinion. Come up with a slightly better UI and you got a winner.
Anyone know of a OP reflector that fits the E05 before I go measuring and searching?
Not me. Sorry. The Olight S15 baton reflector looks mighty close though.