I haven’t tried to remove the switch retaining ring, but I hear it can be gently pried out with a narrow wedge.
Instead, I’ve been using a test host with no switch retaining ring:
This way, I don’t have to open up my regular-use lights until I have the code completely done. I can do the development on more dev-friendly hardware.
It does at least have a “tactical” mode, in case that helps…
I’m not sure what exactly would need to change for tactical use.
Maybe a Strobe and/or a Strike bezel? Would a tail cap switch even be possible with this type of setup?
I love the 2 D4s I have… but it doesn’t hurt to dream. 
I thought all the tactical lights had angry blue Lattice Bright leds for extra disorientation.
Color doesn’t matter much with 4000 lumens at close range. :sunglasses:
I want the bad guy to suffer as much as possible. No way I’m letting him enjoy the gorgeous tint of the 219C.
LOL 
I don’t know if “enjoy” is the word I would use… but, I get your point.
Is that like the wrong end of 9mm vs 40cal.? :smiling_imp: :question:
Shipping notice of the black D4 4000k (yay it went through as thought it might not with showing sold out soon after) and D1 5000k the other day………………cant wait
“tactical” despite Chinese advertising does not mean “bright enough to make you a target”
Speaking of being bright enough to make you a target, that YouTube comment thread has to be the scariest ever.
‘“Small and not bright”. Kind of like the moron sitting in the middle.’
Yup.
If the Founders had had access to this version of their future, they’d have given the country back to Mad King George.
Folks this question is for ToyKeeper and a few other experts on the D4. Why is this light so much brighter than the Astrolux S41/42 lights? Could the D4 guts be transplanted to the Astrolux S42 head? I like the D4 output but I also understand the importance of lots of Copper to slow heat sag and cooking. I thinks the D4 is a good light that could be a great light with Copper mass in the head.
A few pages back someone asked about a holster for their D4. I carry mine with the Maxpedition UFBS Universal Flashlight/Baton Sheath, the height and diameter can be adjusted to carry almost any flashlight. It’s expensive but it works for most all of my lights.
LOL
Nah… only California and New Jersey. 
While I dont have an S41/42, based on the reviews I dont imagine the host has enough mass to make a real difference. A few extra seconds of Turbo? Either one will get too hot to hold very quickly. I just set my D4 thermal config really low call it a day. You wont find a host this small that can sustain 2500+ lumens for any amount of time no matter how much copper it has on it.
Personally, I’m not a fan of the copper heads on the Manker E14II / Astrolux S41.
The copper is effective at getting heat away from the LEDs. However this has a major downside: The outside of the copper head will heat dangerously hot in seconds…. so hot that it’s too hot to touch. This is especially bad for the E14II and S42 where the switch button is in the head, because you may not be able to operate the controls without possibly burning yourself.
The limiting factor won’t be overheated LEDs, rather it will be overheated fingers. To prevent burns you’ll probably need to turn the temp sensor to an even more aggressive setting than on a stock D4 and will get even less time at turbo.
Also, both the Manker E14II and the Astrolux S42 have significantly larger heads than the D4. Sure you could swap the D4’s guts into one of those other lights with a copper head, but you’ll likely end up with a bigger, heavier light that can’t run as long at turbo.
I have a few S41 and 42’s, and the Copper is beautiful. It’s also about triple the weight. My favorite is the Stainless steel bezel and tail, black anodized Aluminum body with Copper head. The Aluminum S42 heats much quicker than the Copper version. I’m getting about twice the run time before it gets too hot.
My Manker E14II’s copper head gets too hot to touch much faster than my D4, all while producing much less light and weighing far more than the D4.
I changed the driver in my s41 xp-g3 to a mtn 17 dd driver and it went from 2300 to 3000 lumens.So the driver in it has alot to do with it.
I have a tactical strobe and party strobe in my new firmware, both with adjustable speed. However, I’m not sure if Hank will be willing to use it. I doubt he’ll go for the strike bezel idea though; all his lights so far have avoided any sharp or pointy parts.
At the moment, strobes are mapped to “click, click, hold”. It’s like a triple click, only the third press gets held longer. It remembers which strobe you last used, and goes to that one first. However, there is a bit of a pre-flash from the first two clicks, so the full-blast strobe probably won’t be as surprising as if the light were completely dark before strobing.
(pre-flash — the first click goes to moon until you let go, then goes to the memorized level on release, then the light turns off when starting the second click… this gives a faster and more intuitive response during regular use, but has the side effect of making strobes a bit less tactical)
The Astrolux lights are less bright for two reasons:
The D4 is brighter because its creator cares about quality and understands more about how to design lights.
However, copper would be helpful for extending the turbo runtime a bit. Copper can hold more heat, and generally is more useful as a heat-sinking material. The D4 could really use more thermal mass, except that this would also increase its actual mass and make it larger / heavier. But, that said, it does pretty well for aluminum. The unihead design and thick MCPCB shelf go a long way toward making it capable of handling heat.
I wouldn’t recommend trying to improve a S42 using parts from a D4. It would be difficult and have very limited returns at best. The most feasible option for a brighter Astrolux is to get a S41, replace its driver, and bypass its springs. It’s pretty close to the original BLF design, only using cheaper parts, so it can be modded back to a more impressive state relatively easily. The S42 is more of a dead end.
What’s the best battery to use on the d4?? Sony vtc5, 5a or vtc6… thanks.
I guess copper head would reduce thermal lag between the body and the driver, leading to more effective thermal control.