Wednesday, February 1, 2012

Steve Ku 40DD Review

This was my birthday present from my wife, so it has a little extra sentimental value.  Even without that extra nudge, this is one hell of a light.

The Steve Ku 40DD is absolutely jam packed with technology.  This one tiny, fingernail-sized light has two tritium inserts, an infinite variable brightness twisty using QTC material, and my version has a Hi CRI LED for more natural color rendition.  All of this for a bargain price of $65 plus shipping and a few bucks for the tritium inserts.  As cutting edge lights go, this one is hard to beat.  One big problem is that the light is not for sale anymore.  Steve Ku, aka Veleno Designs, is one of the finest custom makers out there, did a small initial run and I signed up.  I think he will probably do another one, maybe in Ti this time (the original run was in stainless steel). 

The light presents a familiar dilemma to folks that like gear--no compromises on performance or tech, but not the most convenient thing in the world.  First, it uses small rechargeable batteries, 10180 cells to be exact.  These batteries are hard to find; available, so far as I can tell, only over the Internet.  This is not a light for your survival kit.  Second, the cells are so small that they don't charge well in a normal rechargeable battery charger.  They do fit in the Nano, a great little charging device, but the current is too high and will fry the battery after a few charges.  I had to go buy a specialized charger from a vendor on CPF, cottonpicker's USB charger, which can be found here.  If you can stomach all of that hassle--rechargeables, hard to find batteries, and a weird charger--the reward is an amazing high performance torch.  It is a trade off though and you should be aware of that going into this review.  Do you want a racecar with lots of maintenance and uncompromised performance or do you want a Toyota Corolla with unmatched ease of use and low maintenance but lackluster performance?  Sometimes, very rarely, you get both high performance and ease of use (like the McGizmo Haiku, for example), but generally this is a trade off you have to deal with when getting into the upper echelons of performance in any arena.


It is funny, but this problem exists in a lot of different places.  I call it the "racecar problem."  Very high end audio stuff is a pain in the ass to use, with massive transformers and 250 pound amps, but the performance is stunning.  Similarly, I am sure you work with people like this--if everything is perfect they are wonderful at their task, but if not they get just about nothing done.  Look at a guy like Nomar Garciaparra--when he was healthy he would hit .372.  If he wasn't PERFECTLY healthy though, he was all but useless.  The racecar problem is everywhere.


Here is the CPF Marketplace thread for the 40DD.  There are no other reviews of this light that I can find.  There was another tiny Ku light, the 38DD (the name is a designation for the size of the light, not what your thinking).  Here is a review of that light.  There are obviously no Amazon reviews or other places to get the light so no street price.  Here is my 40DD in its beautiful utility/scratched up finish:

Design: 2

You want a small light.  No, no...a REALLY small light.  Here you go: 


From left to right that is my McGizmo Haiku, my Aeon, a AA battery and the 40DD.  How's that for small?  The idea is that the light can live on a keychain or a neck chain without any problem and still throw up a wall of light.  It isn't a wall of light like I have seen on other flashlights, but for the size it is amazing.  One thing that you might have a problem with though is the twisty.  If you have dawg paws, this is not your light.  Stick with the Photon.  This sucker requires some skillful manipulation and two hands to work.  No finger yoga can get this light to turn on with one hand.  Given its intended use, the size is not an problem, but a benefit.  In terms of day to day use though, it might be too small.  I like it though.  It vanishes in my jeans coin pocket and adds almost nothing to the weight of my EDC.  I like the tritium inserts a lot--they really do work perfectly.  I also like the lanyard attachment, though I have no intent on using it.  The flats work well for a bit of grip (more on that later) and they can, in very steady situations, stabilize the light enough to prevent it from rolling away.  The QTC insert is about as simple as possible, just drop the little bit of material in the battery tube, make sure it is flat and your good to go.  Excellent, small, simple design.

Fit and Finish: 2

Back to the threads for F&F check mantra.  Here the threads are perfectly cut.  This is key to making the QTC material work.  Lots of people complain that the QTC is too finicky, jumping brightness levels rapidly.  Not in the 40DD.  I think a lot of that finicky feel comes from slop in the threads.  Here, in order to activate the light by pressure alone, you have to have the head twisted almost exactly in the on position.  If not you get nothing.  This, in turn, prevents pressure from activating the QTC.  The smooth, precise threads mean you get smooth, precise activation through the QTC pill.  Additionally the tritium inserts were well placed and the reflector fins were cut nicely.  Everything was well done.  I like the matte finish as it picks up wear in the coolest way.  Boba Fett indeed.  

Grip: 0

Let me point out the obvious--there is no way to make this thing grippy.  It is just too small.  Like a gentleman's knife can't be sturdy, a light this small cannot be grippy.  It is just the way it is. 

Carry: 2

Here you have this flashlight, with infinite variable brightness, 100 lumen max output, and it weighs almost nothing.  Carry, as you can imagine, is an absolute delight.  I have never been a fan of bulky stuff, so this shouldn't be a surprise, but I LOVE dropping this thing into a jeans coin pocket or my button down dress shirt and rolling out, knowing that 99.9% of my lighting needs are met by a device that is probably 1/100th the weight everything else I am carrying (especially when I am loaded for court, ugh). 

Output: 2

Steve Ku confirmed for me in an email what my eyes have told me, this little guy is scorching bright, clocking in at around 100 lumens.  Mine, as a Hi CRI model is a little less, but still impressive.  But high highs only mean so much.  Here it is the tasty, almost infinitesimal lows that really do well for me.  I cannot properly photograph the low, but it is well under a lumen, I know that for sure.  It makes other lows look positively bright.  This means the light is useful in all kinds of tasks, again a huge plus in an EDC light.
Runtime: 2

It is hard to calculate a runtime because of the QTC and infinite variable brightness, but I can say I have been very pleased.  I am clocking around two weeks of regular daily use per charge.  And in a package this small and this bright that is really quite nice.   

Beam Type: 2

You can pick your beam type, flood or spot.  Mine, a spot version, is still quite floody (really, there is only so much you can do with a reflector this small).  Overall it is a very nice balance and great for utility tasks. 

Beam Quality: 2

Here is the miracle emitter, the XPG Hi CRI:


Now I know why people are tint snobs.  It does make a difference, a pretty big difference actually.  Reds are red, not maroonish red.  Blues are blue, not sickly blue green.  It is awfully helpful at night, allowing me to distinguish between colors at night.  For example, diapers changing at night is easier (he needs special, "extra pee" nighttime diapers and they are a different colors that are, unfortunately, slight variations of red).  

UI: 2

I am not 100% sold on the need for an infinite variable brightness light, but if there is anyway to make it work, this is it.  A simple twist, twist more UI makes this just about as intuitive a light as can be designed.  Brilliant and excellent.  Also, Steve confirmed that the QTC chip can last 100,000 cycles and he has more if you need it. 

Hands Free: 1

This thing tailstands well, but even with the little flats on the side it has a tough time remaining stationary if laid on its side.  It just wants to roll away at the slightest movement.  I haven't tried the in the teeth move because of the tritium inserts.  They are supposed to be safe, but DRINKING it has to be bad. 

Overall Score: 17 out of 20

This is an amazing little light.  Some of the limitations are inherent in the size, but if you can get past that and the wonky battery, be prepared--this is a really high performance machine.  Only five or ten years ago this gem would have been hands down the best light in the world available to consumers.  Now, it is a darn good light.  The price, $65, makes this an unbelieveable bargain.  Problem is you aren't going to find them for that price on the secondary market.  A few have sold on CPF for around $120-150.  Even that is not a bad deal at all.

Or, and I am glad I can tell you this, I have confirmed today that Steve is doing a run in Ti this April.  Here is more information.  Tell him you heard about this on Everyday Commentary.  Enjoy some tiny, tasty, Ti goodness.      


  1. Is there a price on the Ti version? I didn't see it on cpf. Also the Ti looks to be called the "44DD" - is everything the same except the material?

    1. the 44dd is all the same, except 4mm longer. he is switching the battery from 10180 (hard to find) to 10220 (easier to get)
      otherwise the same. price will be about the same as the original 38DD in Ti (maybe +-80 bucks a pop depending on the finish?)

  2. LOL on the diaper selection! It's always interesting to hear how people use their lights.

  3. Looks like the new light will be slightly bigger with a slightly larger battery, a 10220, I think.

    As for the diaper thing, this is a perfect night time light. The low is so low that it will wake up no one and the thing tail stands like a champ.

  4. Sounds like a great little light, would love to compare it to my Lummi Wee. Love the props for Enrique w/ your Aeon, they are awesome. I own an Aeon and a Nautilus and they are both awesome little lights.

  5. I've been using the nano charger for 10180 batteries for a while now. The charge rate isn't actually as high as what the specifications state, and the charge rate drops quickly as the battery is charged up. From my tests, I don't think its a big issue using the nano charger.

    Thanks for the review, sorta makes me wish I got one too. I'll just stick to my 38DD, with modified pill

  6. Great review, Tony! I was lucky enough to find a 38 DD Ti just before Christmas and I love it. I had a 40 DD on order but couldn't get past the blasted finish. I prefer the finish on the 38DDs. These are amazing little lights.