K40 Defuser Optix Laser Jammer Review

K40 Defuser Optix Overview


The K40 Defuser Optix ($899 for duals) is K40’s top of the line laser jammer. It’s smaller and more effective than their previous bulky K40 G5’s. The Defuser Optix is designed to integrate with the RL200di and RL360di radar detectors. (Read my RL360di review.)

K40 also claims that the Defuser Optix is able to jam the DragonEye. (K40 refers to their laser jammers as “laser defusers,” similar to how Escort refers to them as “laser shifters,” but they’re all really the exact same thing.)

Let’s take a closer look at the K40 Defuser Optix and how effective it truly is in this review.

K40 Defuser Optix laser defusers

K40 Defuser Optix

K40 Defuser Optix Features & Highlights

  • Compact head size, similar to the competition
  • Support for up to 5 heads total
  • Integrates with the K40 RL200di and RL360di radar detectors
  • Laser jamming effectiveness is subpar
  • Advertised with DragonEye jamming capabilities, but this is poor in practice
  • Unlimited jam time by default
  • 5 second AutoJTK available as an option
  • Laser detection only (laser jamming disabled) available as an option
  • USB port for firmware updates
  • Retails for $899 for duals (more expensive than nearly every other jammer on the market)

Laser Defuser Head Design

K40 Defuser Optix head

K40 Defuser Optix head

One of the biggest improvements with the new K40 defuser heads is that they’re physically much smaller. Instead of using a series of IR transmitting LED’s like they used in their last gen K40 G5 (here’s an old G5 test), the new Defuser Optix uses a laser diode transmitter instead. Using a diode, you get a smaller package and a better performing jammer.

Size-wise, the head design and size is comparable to what we see from companies like Escort and AntiLaser.

ALP vs K40 Defuser Optix head size comparison

AntiLaser Priority and K40 Defuser Optix heads (photo courtesy of RALETC)

Smaller heads make the heads easier to install, they can fit into tighter spaces, and they’re much less visible once installed on your vehicle.

K40 Defuser Optix installed in grill

K40 Defuser Optix installed in grill

Laser Defuser Performance Test

Next let’s talk about how effective the laser jammer is. If it doesn’t jam well, nothing else really matters.

Last month I tested the K40 Defuser Optix (installed as a set of triples) against all the other top laser jammers on the market.

Laser jammer heads labeled in grill

K40 Defuser Optix installed alongside other laser jammers for testing

Unfortunately the Defuser Optix turned in a last place finish, struggling to jam both the newest laser guns with anti-jamming technology as well as even the older and more traditional laser guns.

K40 Defuser Optix Test Results

The only gun it was solid against was the Kustom ProLaser III which is one of the most common laser guns in use nationwide.

Against more medium difficulty guns like the Stalker XLR and LTI TruSpeed S, it did well when we targeted my driver’s headlight, but we kept getting punchthroughs when targeting the front license plate (center mass) as well as the passenger headlight.

Against the DragonEye SpeedLidar and DragonEye Compact, it wasn’t able to jam whatsoever. In fact, it didn’t even alert to those guns. Every other laser jammer tested alerted and jammed (with varying levels of success). The K40 was the only laser jammer that wasn’t even able to alert to the DragonEye.

DragonEye Jamming

K40’s DragonEye Tests

K40 specifically claims that it can jam the DragonEye, but there’s some conflicting information out there.

Now K40 does have some videos online showing the Defuser Optix apparently jamming a Compact.

There’s always been a lot of speculation around the legitimacy of these videos for multiple reasons. One of the reasons, for example, is you’ll notice the shooter’s finger moves off the trigger on the close up of the gun, but not in the clip of the shooter aiming towards the car. Is it just two different test runs edited together and not the same run or is there something more going on?  It’s tough to say. Without a camera aimed through the gun’s viewfinder, a lot of people question the veracity of the manufacturer’s videos, especially since most third party testers have found different results.

RALETC’s DragonEye Test

RALETC tested the Defuser Optix against a DragonEye and like me, they found that the jammer didn’t alert at all, much less jam. Take a look for yourself:

PY004’s DragonEye Test

In yet another test, @PY004 on RDF tested a Defuser Optix (duals) and while he didn’t have great results overall either, he did have better results against the DragonEye.

PY004 K40 Defuser Optix Dual Test Results

Similar to my findings, he found the K40 struggled against even the easier guns.

Against the DragonEye, it managed to jam all the way down to 150 ft when targeting center mass. It not only detected, but it also jammed pretty effectively too. Against the headlights though, it was instant punchthough (IPT).

What’s up with all these discrepancies?

Can K40 Jam the DragonEye?

DragonEye Compact laser gunWell there isn’t just one version of “the DragonEye.” There’s many different versions of the gun that operate completely differently and send out completely different pulse patterns. Heck, even with the same gun, every time the officer pulls the trigger, the gun sends out a brand new unique pulse pattern which is what makes it so tricky.

Depending on the algorithm that the laser jammer is using, the jammer may be effective against some versions of the guns and not others. It may also be effective against one particular gun sometimes, but not in every single test pass. There’s many variables at play here when we talk about “jamming the DragonEye.”

It looks like the K40 is sort of able to jam older versions of the gun, but not consistently. Against new versions, it is completely useless.

“When I tested months ago with the oldest common version of the DETC it didn’t alert to that either most of the time. Sometimes it would but it would IPT.” -Jon at Radenso

So while the K40 Defuser Optix does have some semblance of DragonEye jamming capabilities, especially against older variants, it is not consistent or reliable in its jamming. Against newer DragonEyes, it neither alerts nor jams whatsoever. With the Defuser Optix installed, it’s essentially like you’re not running jammers at all.

Now when I called K40 before I did my testing and asked them about how they handled the DragonEye, they said that the Defuser Optix can indeed jam the DragonEye, but if there’s newer variants that have come out more recently that they haven’t yet updated to support, they wouldn’t be able to jam those guns. That’s a pretty fair answer and I appreciated them being straightforward with me. Unfortunately though, their current level of protection is unsatisfactory, IMHO, as is their history of continued updates and improvements.

Firmware Updates

K40 Defuser Optix CPU

K40 Defuser Optix CPU

Firmware updates are critical when it comes to laser jammers, even moreso than with radar detectors. It’s a cat and mouse game between laser guns and laser jammers. As laser gun manufacturers update, laser jammer manufacturers need to update accordingly. One of the most common updates we see from laser jammer manufacturers are periodic improvements to improve jamming capabilities, especially as newer and tougher laser guns are released.

The K40 Defuser Optix was released back in 2016 and hasn’t received a single update to date. Not one. It shocked me to find this out. (I wanted to make sure I was running the latest firmware before testing which is why I asked.)

The competition releases updates and improvements every few months or so. K40 hasn’t released a single update yet the 3 years it’s been on the market.

RALETC’s test was conducted and released in 2016 so it’s not like K40 is unaware of their product’s limitations.

The Defuser Optix has a USB port built into its CPU specifically for update purposes, but unless K40 chooses to actively support their products through firmware updates and continued improvements, their laser jammer will continue to lag behind the competition.

Now RALETC also did a teardown of the K40 Defuser Optix and in their teardown, they found that K40 is using pretty basic and simple hardware. Under the hood it’s very different compared to what we see from competitive jammers that are effective against the DragonEye. The best performing laser jammers use much more sophisticated and powerful hardware to achieve this. So assuming K40 does decide to one day update their laser jammers, I don’t know if their hardware can even support jamming the latest versions of different laser guns currently out on the market.

Speeding Ticket Guarantee

K40 Ticket Free Guarantee

K40 offers a speeding-ticket guarantee (with some fine print and exclusions on their website).

“Get a ticket during the first year of ownership, we pay for it, subject to the terms and conditions below. Simply send us a copy of the radar or laser speeding ticket, your proof of payment of the ticket, and your receipt for your K40 purchase.”

I think speeding ticket guarantees are great as an additional layer of protection. IMO, guarantees are great, particularly as a marketing tool. They are very effective in generating sales which is why other manufacturers now offer them too. However, I’d personally choose a laser jammer that works well in the first place, regardless of any guarantees.

This way I can not only avoid getting a speeding ticket, but also avoid getting pulled over, the headache involved, any hikes to my insurance, as well as any potential court costs or lawyer fees. They’ll reimburse you for the cost of the ticket, but not for everything else which is usually much more substantial.

Performance Guarantee

Speaking of guarantees, K40 has another that caught my eye:

“If your K40 Radar Detector or Laser Defuser does not outperform any other radar or laser protection system you’ve owned, return it within 30 days for a full product credit.”

That’s what I’m curious to know and it’s why I test and use them all: to see which laser jammer performs best. (You can read my thoughts on the best laser jammers here.)

Unfortunately, just like when I tested the K40 RL360di radar detector, the K40 Defuser Optix laser jammer turned in a bottom of the barrel result. Fortunately I can confirm that I was able to get a complete refund for the K40 system I purchased. K40’s guarantee doesn’t also cover install and uninstall costs though, so keep that in mind.

Is the K40 Defuser Optix Any Good?

K40 logo

In my opinion, no. The K40 Defuser Optix is a not a good laser jammer to run in this day and age.

While it is an improvement compared to K40’s previous gen jammers, it continues to struggle to reliably jam older guns and it is 100% ineffective against the newest and toughest laser jammers on the market.

I understand that some people like their K40 products and that’s great, but unfortunately the performance of their products simply doesn’t compare to the competition. The same is true with their radar detector. Read my K40 RL360di radar detector review.

There are a lot of great laser jammers out there, but the K40 Defuser Optix is not one of them.

If you are looking for a good quality laser jammer to keep you protected, I’d recommend you skip the K40. Instead, click here to read my top picks for the very best laser jammers.

Update: K40 has had a chance to read and respond to my review. Click here to read K40’s response to my review.

This website contains affiliate links and I sometimes make commissions on purchases. All opinions are my own. I don’t do paid or sponsored reviews.

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Review Date
Reviewed Item
K40 Defuser Optix
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K40 Defuser Optix

Permanent link to this article: https://www.vortexradar.com/2019/07/k40-defuser-optix-laser-jammer-review/


Skip to comment form

    • Brent Russell on January 25, 2021 at 11:38 am
    • Reply

    Your link to the k40 response doesn’t go anywhere.

    1. Sorry you’re right. Thanks for letting me know. I fixed the broken link. Here’s the link to their response as well.

    • Brent on February 23, 2021 at 9:02 am
    • Reply

    I talked with K40, they claim to have new diffusers. I really want to like their system but your reviews have me holding off for now. Any chance you might be retesting in the near future. I really appreciate your thoroughness. Your website and videos have done a great job in educating me. Thank you!

    1. Did they give any details regarding what changed specifically? They have released a new radar detector recently with slightly longer range, but they’re still selling the same Defuser Optix on their website.

    • Brent on February 24, 2021 at 7:00 am
    • Reply

    I got some bad information from an installer, confirmed with K40 that the latest diffuser was from some time ago. Sorry for the confusion

    1. Thanks for the followup!

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