SureFire KL1
Note: This page has at least 22 images on it; please be patient.

SureFire KL1, retail $39-$56 (
Manufactured by SureFire (
Last updated 11-17-09

The KL1 is SureFire's new Luxeon Star based replacement bezel for your existing SureFire E1 or E2 series light. SureFire is well-known for making the toughest and brightest personal and tactical lights in the world, and the new KL1 will not disappoint you. The KL1 will work from 3 to 9 volts (that's 1, 2, or 3 CR123A lithium cells) and is designed specically to fit SureFire's E-series flashlights.

The tidy, compact unit screws directly onto the body of your existing E1-series and E2 series light. I was provided with an E2e body to test and evaluate the KL1 with. The KL1 includes a regulator circuit that assures you a rock-steady output all the way until the batteries expire. I tested the KL1 in the Executive Elite E2 body (2x CR123 cells) and was consistently rewarded with 4.5 hours of fully-regulated light before it began to fall out of regulation and start to dim.


Using the KL1 is simple. All you do is unscrew the bezel & lamp assembly off your E1 or E2 series light, and screw the KL1 bezel on. The switching mechanism will depend on what type and vintage of light you have; but you will always have a choice of momentary operation by pressing the rubber button on the tailcap, or continuous burning by twisting the tailcap in clockwise. Some models also feature a lock-out tailcap; but otherwise function as above.

The KL1 does not in any way modify your original light, so you are free to switch back to the regular bezel & lamp assembly any time you wish.

Change the batteries in your KL1-equipped light the same way you always did: unscrew & remove the KL1 bezel, change the batteries, and screw the KL1 back in place. Be sure the batteries are installed with the button (+) end facing up.

Two battery discharge analyses. The first was hand-plotted on-the-fly; the second was fully automated and machine-made using an auto-ranging plotter for less chance of error.

As you can see by the charts, the KL1 remains 100% in regulation for nearly 4 1/2 hours, then drops off over the next hour or so and finally levels off into a stable "moon mode" that provides more than enough light to use in an emergency - about the equivalant of a good single-LED flashlight for many hours after it drops out of regulation.

The KL1 is extremely well-made and engineered. The same SureFire quality you've come to expect from their personal and tactical lights is built into the KL1. The finish is a type 3 hard anodize, just like the rest of the SureFire light you installed it on.

A Pyrex window protects the "new style" Luxeon Star collimator from scratches and impacts. One thing I noticed as soon as I opened the evaluation sample was just how clean the collimator was. There were no fingerprints or dust on it. In all other non-SureFire Luxeon products I've seen to date, this component was contaminated with fingerprints - in some cases, enough for CSI to get a match on. In one product, there was even a milky-white salty residue from a drop of human sweat that had fallen on the inside of the collimator, and was subsequently sealed inside the product! But not the KL1! Its optics are crystal clear and absolutely spotless. Any dust specks you see in the photos on this page landed there *after* I received the product, not before.

The beam produced by the KL1 is virtually perfect: a bluish-white central hot area that's almost perfectly centered (virtually impossible given the state of Luxeon Star technology today), fading to a perfectly circular white corona which has a moderately abrupt edge. Beyond this lies a much fainter, slightly greenish white outer corona that pretty much fades to nothing a few degrees farther out. As I have nothing to measure beam angles directly, you'll have to wait until I run the KL1 through the beam profile analyzer before exact figures will be known.

The KL1 is outfitted with a very good regulator circuit. In my tests, it keeps the light output rock steady for well over four hours on a set of two SureFire brand CR123A cells. I would expect similar performance from other brands, given the KL1 does not have an insanely high current drain like an incandescent lamp would.

Beam photo.
Measured a whopping 351,000mcd at beam center.
Current consumption is only 380 milliamps in a 2-cell light like the E2 or E2e.

Spectrographic plot
Spectrographic analysis of the LED in this flashlight.

Spectrographic plot
Same as above; newer spectrometer software & settings used.
USB2000 spectrometer graciously donated by P.L.

ProMetric analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.

Evaluation units were tested in August 2002 just prior to their commercialisation with detailed reports sent to SureFire before this page was constructed. Many thanks to PK at SureFire.

UPDATE: 09-18-02
This page is just now being written, and more data will be added in the coming days. However, I have already tested this product for about one month and have already assigned a final product rating, so you can buy with confidence.

UPDATE: 05-20-03
I have been told this bezel retails for $56, but can be found for $39 at County Comm and $45 at Island Security (URL not available).

This assumes you already have an E-series body to put it on, and a pair of 123 lithium cells to feed it.

UPDATE: 09-29-04
A "new style" KL1 LED bezel is now available.
This uses what I believe is a high-dome (lambertian) Luxeon LED, as opposed to the low-dome (batwing) emitter found in the original KL1. This plus the EOS phosphor deposition process on the LED itself renders the output sigificantly whiter than what is normally seen in low-dome emitters.

A curved Pyrex window protects the LED optic. The new KL1 utilizes a new TIR (Total Internal Reflection) optic. It is not acrylic, and not polycarbonate. It's made out of optical grade special resin.
The new KL1 is substantially brighter than the original too.
351,000mcd for the original vs. 1,140,000mcd for the new style.

Notice if you will too, that the new style KL1 bezel does not have those circular fins around it like the original does. It is designed more like the SureFire KL4, with mainly smooth sides and some gentle (not deep) U-shaped cutouts machined into it. The end of the bezel is also scalloped, so you can tell if you left your KL1 on even when it is set face-down on a flat surface like a counter, table, shelf, or dresser. Yes, I ruined the batteries this way (by setting it face-down on a dresser and not realising it was on) in a SureFire KL2 when I was first evaluating it.

This bezel has PK (Paul Kim) autographed on it. This is a production manufacture, which is exactly what you'll receive when you order. The only difference between this bezel and the one you'll receive is that mine is autographed.

New style KL1 bezel on top, original style KL1 bezel on the bottom.
The new style bezel is approximately 0.15" longer than the original.

Original KL1 bezel; measures 351,000mcd at a current draw of 380mA.
Has a distinct purplish tint that was not reproduced very well in this photograph.

New style KL1 bezel; measures 1,140,000mcd at a current draw of 632mA
Note the central hotspot is smaller and significantly whiter than the one from the original KL1.

Beam photograph of the new style KL1 bezel; taken at ~4' and deliberately underexposed by two stops to show any details that an overexposed photograph might miss.

UPDATE: 11-14-09

Spectrographic plot
Spectrographic analysis of the LED in this newer-style KL1 bezel.
USB2000 spectrometer graciously donated by P.L.

ProMetric analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.

Neither KL1 has that "rotten cat urine green" tint to their beam perimeters as you might see in the first two of these three beam photographs.

Insanely bright (even more so with new style)
Excellent construction & engineering
Excellent beam quality
Fully regulated with rock-steady light output

Slight body color mismatch, however this is normal with the HA-3 process, and will not figure into my rating.

    PRODUCT TYPE: LED Bezel for SureFire lights
    LAMP TYPE: Luxeon Star LED
    No. OF LAMPS: 1
    BEAM TYPE: Circular with central bluish-white hot spot
    SWITCH TYPE: Varies depending on the light you install it in
    BEZEL: Pyrex lens with emitter & optic positioned directly beneath
    BATTERY: 1x or 2x CR123A Lithium Photo Battery
    CURRENT CONSUMPTION: 380mA at 6 volts
    SUBMERSIBLE: To shallow depths at minimum
    ACCESSORIES: None that I'm aware of
    WARRANTY: Lifetime


    Star Rating


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