Hi Stefano.
I live in city and it’s difficult exterior photos. If you can wait 2 or 3 days, I try to compare Wk41, wk42, E11, with outdoors pics.
For me the best of the 3 is the WK42. No problem with the size of the primary or rechargeable batteries. Its power is very good with rechargeable RCR123A Lithium. But if your friend does not use Lithium, WK41 be better. People do really like the low battery warning.
Hola Trevi
Thanks for the quick response.
The torch is for a girl (not flasholic) I do not think it will use RCR123, I could give a battery of these but then there's the problem of the lack of autonomy of RCR.
Warning of low battery is good for inexperienced user.
WK42 looks interesting for a woman, the small size are well suited to a woman's bag.
I'm really torn between the two models, even the WK41 is small and looks very handy to put in a bag woman.One question: XTAR both have ability to turn on the light directly on the turbo? (ideal for defense)
Fenix E11 I like to switch back easy to find even in the dark.
Translated with Google Translate
Hi
The wk have memory, they turn on in turbo, but only if you turn off turbo.
For non flasholic, I dismiss the wk42. Better AA NiMH batteries.
If I need defense flashlight, really 3.7V are required, 1.5 or 1.2V AA does not give enough power to defense.
I would choose the E11 or Wk41 and will also give away a package of ultimate energizer L91 (but this does not serve to self defense)
Thanks for the tips, I am aware that it takes for defense flashlight with many lumens.
Together with the torch (WK or E11) gift a charge XTAR XP1 and Eneloop Black.
I found the throw indicated on the website XTAR, 60 meters for WK41, 65 meters for WK42
These values increase much with 14500 or 16340 battery (XTAR declares: 115 meters for Wk 41 and 100 meters for WK42)
The XTAR is a flashlight with superior features but I did have a lot of opinion that flood as the Zebralight.
Even 2xAA Model WK40 is declared only 70 meters
They are 85 meters for the new Fenix E11 (115 lumens model) or 74 meters for the old model 105 lumens.
I think that these values ??are suffienti for both cases, I think the gift will certainly XTAR WK41 or 42
But as a fan of lights I'd like to see some comparison between Fenix ??E11 and WK41 with AA batteries
This evening I tried to take some pictures but my camera equipment is of poor quality (Coolpix L25)
I can only show two photos acceptable, Fenix ??E11 old model (105 lumens)
Photo 1 - 30 lumens power
Photo 2 - 105 lumens power
My Xtar WK41 just arrived yesterday.
The anodizing and build quality felt excellent. Anodizing is perfect. the knurling is very well done and provides a good grip, and the switch is small and recessed enough that I doubt it would accidentally turn-on in the pocket. The beam pattern is excellent for short range work.
The head of the light disassembled easily. There was no threadlocker. In unscrewed the bezel and the lens and reflector popped out. I removed the isolator disk revealing a standard 16 mm star, nicely lubed with thermal grease on the back.
The driver and physical reverse polarity protection insert are held in with 2 small screws at the back of the head. Unscrew those and the driver came right out. As expected, there were 2 pieces: one piece being the driver (looked to be around 19mm or so), plus a small rectangular piece holding the switch. The switch portion fitted into a slot in the head and was kept in place by the driver board.
The light isn’t perfect though. The interface left a bit to be desired. Click to turn on, then click repeatedly to advance through the modes. There’s a shortcut to strobe, but no shortcut to min or max. The emitter is also a bit dated, being an XML and not an XML2, and it’s cool instead of neutral. Turning off the light feels awkward as you have to hold down the button for 2 seconds. If you’re at high and click once, it will go to low power, but won’t turn off. This is tricky, given that on most other lights 1 click turns the light off. With the WK41 you might click once and think it’s off, not realizing it has actually just cycled to low.
Also, output was less than I’m used to. On Li-ion, this light only produces 300 lumens on turbo. I’m used to pocket rights like the SC52, RRT-01 and EYE10 that all easily produce 500 lumens or more.
Three and a half hours of modding later:
The result. running on a Kinoko IMR 750 Mah 14500: Much, much, MUCH brighter than before. It’s noticeably brighter than my modded Jetbeam RRT-01 (running on an EYE10 driver, Kinoko IMR 18350, and an XML2 T6 neutral on copper).
My modded Xtar WK41 now has a beautiful neutral tint. The new driver has shortcuts to minimum, 10% and max, and has 2-way ramping. The outside of the light looks and feels the same as the original.
I’m pretty pleased with how this mod came out, and how fast it was to assemble. The entire mod took less than 4 hours, which is pretty good for me. This light was just a joy to work on.
Thanks for a nice review.
I’m wondering if the WK41 has any PWM, detectable by eye, especially in the lower modes?
That might decide if I will buy it or not, because I find PWM annoying. Their other model WK50 has very noticable PWM in every mode except the highest.
Thanks.
I have one and it doesn’t 
That’s great, I might get one then
I just got mine, and it does unfortunately have PWM on all modes except the highest, making it far less nice to use than a flashlight which has a consistent light beam.
The fact whether a flashlight has PWM or not would be important to include in a review as well.
You can see easily if a flashlight has PWM by having it on and moving it in an arc in front of you, and you will see in the air a series of short flashes instead of a solid arc of light.
You can also see it, though not as easily, while paying attention to any point that reflects the light from the flashlight, and moving your eyes quickly, then you can see the reflective point as a series of “pictures,” rather than it moving smoothly in your field of view.
Sorry 
but I didn’t detect any… hmmn
No problem, it’s still a good flashlight, and got it for half price on eBay promotion.